U.S. patent application number 16/688372 was filed with the patent office on 2020-05-21 for method for transmitting and receiving data channel in communication system and apparatus for the same.
This patent application is currently assigned to ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE. The applicant listed for this patent is ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE. Invention is credited to Seung Kwon BAEK, Cheul Soon KIM, Sung Hyun MOON, Gi Yoon PARK, Ok Sun PARK, Jae Su SONG.
Application Number | 20200162208 16/688372 |
Document ID | / |
Family ID | 70728235 |
Filed Date | 2020-05-21 |
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United States Patent
Application |
20200162208 |
Kind Code |
A1 |
MOON; Sung Hyun ; et
al. |
May 21, 2020 |
METHOD FOR TRANSMITTING AND RECEIVING DATA CHANNEL IN COMMUNICATION
SYSTEM AND APPARATUS FOR THE SAME
Abstract
Disclosed are methods and apparatuses for transmitting and
receiving data channels in a communication system. An operation
method of a terminal in a communication system may comprise
receiving, from a base station, resource allocation information of
a plurality of physical uplink shared channels (PUSCHs) used for
repetitive transmission of a same transport block (TB); identifying
a position of each of the plurality of PUSCHs in a time domain
based on the resource allocation information; and repeatedly
transmitting the same TB to the base station at the position of
each of the plurality of PUSCHs. Therefore, performance of the
communication system can be improved.
Inventors: |
MOON; Sung Hyun; (Daejeon,
KR) ; KIM; Cheul Soon; (Daejeon, KR) ; BAEK;
Seung Kwon; (Daejeon, KR) ; PARK; Gi Yoon;
(Daejeon, KR) ; PARK; Ok Sun; (Daejeon, KR)
; SONG; Jae Su; (Daejeon, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE |
Daejeon |
|
KR |
|
|
Assignee: |
ELECTRONICS AND TELECOMMUNICATIONS
RESEARCH INSTITUTE
Daejeon
KR
|
Family ID: |
70728235 |
Appl. No.: |
16/688372 |
Filed: |
November 19, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 1/1896 20130101;
H04L 1/1816 20130101; H04W 72/042 20130101; H04W 72/1268 20130101;
H04W 72/1289 20130101; H04W 72/0446 20130101; H04L 1/08 20130101;
H04W 76/27 20180201 |
International
Class: |
H04L 1/18 20060101
H04L001/18; H04W 72/04 20060101 H04W072/04; H04W 76/27 20060101
H04W076/27 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 21, 2018 |
KR |
10-2018-0144903 |
Dec 12, 2018 |
KR |
10-2018-0160282 |
Apr 17, 2019 |
KR |
10-2019-0045096 |
Nov 7, 2019 |
KR |
10-2019-0141479 |
Claims
1. An operation method of a terminal in a communication system, the
operation method comprising: receiving, from a base station,
resource allocation information of a plurality of physical uplink
shared channels (PUSCHs) used for repetitive transmission of a same
transport block (TB); identifying a position of each of the
plurality of PUSCHs in a time domain based on the resource
allocation information; and repeatedly transmitting the same TB to
the base station through the plurality of PUSCHs at the position of
each of the plurality of PUSCHs.
2. The operation method according to claim 1, wherein the resource
allocation information includes information indicating a start
symbol of each of the plurality of PUSCHs and information
indicating a number of consecutive symbols constituting each of the
plurality of PUSCHs in the time domain.
3. The operation method according to claim 2, wherein a start
symbol of at least one PUSCH among the plurality of PUSCHs is
indicated by a symbol index or an offset between a previous slot
boundary and the start symbol.
4. The operation method according to claim 1, wherein the resource
allocation information includes information indicating an offset
between a slot in which the resource allocation information is
transmitted and a slot to which at least one PUSCH among the
plurality of PUSCHs is allocated.
5. The operation method according to claim 1, wherein the resource
allocation information includes information indicating a number of
slots in which the plurality of PUSCHs are transmitted.
6. The operation method according to claim 5, wherein one PUSCH is
transmitted in one slot when the number of slots is equal to a
number of the plurality of PUSCHs, and two or more PUSCHs are
transmitted in at least one slot when the number of slots is less
than the number of the plurality of PUSCHs.
7. The operation method according to claim 5, wherein the slots in
which the plurality of PUSCHs are transmitted are contiguous in a
time domain.
8. The operation method according to claim 1, wherein the resource
allocation information is received from the base station through
downlink control information (DCI) or radio resource control (RRC)
signaling.
9. The operation method according to claim 1, further comprising
receiving resource allocation candidates of the plurality of PUSCHs
from the base station through RRC signaling, wherein the resource
allocation information indicates one resource allocation candidate
among the resource allocation candidates, and the resource
allocation information is received through DCI.
10. An operation method of a base station in a communication
system, the operation method comprising: generating resource
allocation information of a plurality of physical uplink shared
channels (PUSCHs) used for repetitive transmission of a same
transport block (TB); transmitting the resource allocation
information to a terminal; and receiving the same TB from the
terminal through the plurality of PUSCHs indicated by the resource
allocation information.
11. The operation method according to claim 10, wherein the
resource allocation information includes information indicating a
start symbol of each of the plurality of PUSCHs, information
indicating a number of consecutive symbol(s) constituting each of
the plurality of PUSCHs in a time domain, information indicating an
offset between a slot in which the resource allocation information
is transmitted and a slot to which at least one PUSCH among the
plurality of PUSCHs is allocated, and information indicating a
number of slots through which the plurality of PUSCHs are
transmitted.
12. The operation method according to claim 11, wherein a start
symbol of at least one PUSCH among the plurality of PUSCHs is
indicated by a symbol index or an offset between a previous slot
boundary and the start symbol.
13. The operation method according to claim 11, wherein one PUSCH
is received in one slot when the number of slots is equal to a
number of the plurality of PUSCHs, and two or more PUSCHs are
received in at least one slot when the number of slots is less than
the number of the plurality of PUSCHs.
14. The operation method according to claim 10, wherein the
resource allocation information is transmitted to the terminal
through downlink control information (DCI) or radio resource
control (RRC) signaling.
15. The operation method according to claim 10, further comprising
transmitting resource allocation candidates of the plurality of
PUSCHs to the terminal through RRC signaling, wherein the resource
allocation information indicates one resource allocation candidate
among the resource allocation candidates, and the resource
allocation information is transmitted through DCI.
16. A terminal in a communication system, the terminal comprising a
processor and a memory storing at least one instruction executable
by the processor, wherein the at least one instruction configures
the processor to: receive, from a base station, resource allocation
information of a plurality of physical uplink shared channels
(PUSCHs) used for repetitive transmission of a same transport block
(TB); identify a position of each of the plurality of PUSCHs in a
time domain based on the resource allocation information; and
repeatedly transmit the same TB to the base station through the
plurality of PUSCHs at the position of each of the plurality of
PUSCHs.
17. The terminal according to claim 16, wherein the resource
allocation information includes information indicating a start
symbol of each of the plurality of PUSCHs, information indicating a
number consecutive of symbols constituting each of the plurality of
PUSCHs in the time domain, information indicating an offset between
a slot in which the resource allocation information is transmitted
and a slot to which at least one PUSCH among the plurality of
PUSCHs is allocated, and information indicating a number of slots
through which the plurality of PUSCHs are transmitted.
18. The terminal according to claim 17, wherein a start symbol of
at least one PUSCH among the plurality of PUSCHs is indicated by a
symbol index or an offset between a previous slot boundary and the
start symbol.
19. The terminal according to claim 17, wherein one PUSCH is
transmitted in one slot when the number of slots is equal to a
number of the plurality of PUSCHs, and two or more PUSCHs are
transmitted in at least one slot when the number of slots is less
than the number of the plurality of PUSCHs.
20. The terminal according to claim 16, wherein the at least one
instruction further configures the processor to receive resource
allocation candidates of the plurality of PUSCHs from the base
station through RRC signaling, wherein the resource allocation
information indicates one resource allocation candidate among the
resource allocation candidates, and the resource allocation
information is received through DCI.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to Korean Patent
Applications No. 10-2018-0144903 filed on Nov. 21, 2018, No.
10-2018-0160282 filed on Dec. 12, 2018, No. 10-2019-0045096 filed
on Apr. 17, 2019, and No. 10-2019-0141479 filed on Nov. 7, 2019
with the Korean Intellectual Property Office (KIPO), the entire
contents of which are hereby incorporated by reference.
BACKGROUND
1. Technical Field
[0002] The present disclosure relates generally to a technique for
transmitting and receiving a data channel in a communication
system, and more specifically, to a method for transmitting and
receiving a data channel for a service requiring high reliability
and low latency.
2. Related Art
[0003] The communication system (hereinafter, a new radio (NR)
communication system) using a higher frequency band (e.g., a
frequency band of 6 GHz or higher) than a frequency band (e.g., a
frequency band lower below 6 GHz) of the long term evolution (LTE)
(or, LTE-A) is being considered for processing of soaring wireless
data. The NR communication system may support not only a frequency
band below 6 GHz but also 6 GHz or higher frequency band, and may
support various communication services and scenarios as compared to
the LTE communication system. For example, usage scenarios of the
NR communication system may include enhanced mobile broadband
(eMBB), ultra-reliable low-latency communication (URLLC), massive
machine type communication (mMTC), and the like.
[0004] In order to satisfy the URLLC requirements in the NR
communication system, the same transport block (TB) may be
repeatedly transmitted through a plurality of data channels (e.g.,
physical downlink shared channel (PDSCH), physical uplink shared
channel (PUSCH), and physical sidelink shared channel (PSSCH)). For
the repeated transmissions of the same TB, methods are needed for
indicating the plurality of data channels.
SUMMARY
[0005] Accordingly, exemplary embodiments of the present disclosure
provide a method for transmitting and receiving a data channel for
a service requiring high reliability and low latency in a
communication system.
[0006] According to an exemplary embodiment of the present
disclosure, an operation method of a terminal in a communication
system may comprise receiving, from a base station, resource
allocation information of a plurality of physical uplink shared
channels (PUSCHs) used for repetitive transmission of a same
transport block (TB); identifying a position of each of the
plurality of PUSCHs in a time domain based on the resource
allocation information; and repeatedly transmitting the same TB to
the base station at the position of each of the plurality of
PUSCHs.
[0007] The resource allocation information may include information
indicating a start symbol of each of the plurality of PUSCHs and
information indicating a number of symbols constituting each of the
plurality of PUSCHs in the time domain.
[0008] A start symbol of at least one PUSCH among the plurality of
PUSCHs may be indicated by a symbol index or an offset between a
previous slot boundary and the start symbol.
[0009] The resource allocation information may include information
indicating an offset between a slot in which the resource
allocation information is transmitted and a slot to which at least
one PUSCH among the plurality of PUSCHs is allocated.
[0010] The resource allocation information may include information
indicating a number of slots in which the plurality of PUSCHs are
transmitted.
[0011] One PUSCH may be transmitted in one slot when the number of
slots is equal to a number of the plurality of PUSCHs, and two or
more PUSCHs may be transmitted in at least one slot when the number
of slots is less than the number of the plurality of PUSCHs.
[0012] The slots in which the plurality of PUSCHs are transmitted
may be contiguous in a time domain.
[0013] The resource allocation information may be received from the
base station through downlink control information (DCI) or radio
resource control (RRC) signaling.
[0014] The operation method may further comprise receiving resource
allocation candidates of the plurality of PUSCHs from the base
station through RRC signaling, wherein the resource allocation
information indicates one resource allocation candidate among the
resource allocation candidates, and the resource allocation
information is received through DCI.
[0015] According to another exemplary embodiment of the present
disclosure, an operation method of a base station in a
communication system may comprise generating resource allocation
information of a plurality of physical uplink shared channels
(PUSCHs) used for repetitive transmission of a same transport block
(TB); transmitting the resource allocation information to a
terminal; and receiving the same TB from the terminal through the
plurality of PUSCHs indicated by the resource allocation
information.
[0016] The resource allocation information may include information
indicating a start symbol of each of the plurality of PUSCHs,
information indicating a number of consecutive symbol(s)
constituting each of the plurality of PUSCHs in a time domain,
information indicating an offset between a slot in which the
resource allocation information is transmitted and a slot to which
at least one PUSCH among the plurality of PUSCHs is allocated, and
information indicating a number of slots through which the
plurality of PUSCHs are transmitted.
[0017] A start symbol of at least one PUSCH among the plurality of
PUSCHs may be indicated by a symbol index or an offset between a
previous slot boundary and the start symbol.
[0018] One PUSCH may be received in one slot when the number of
slots is equal to a number of the plurality of PUSCHs, and two or
more PUSCHs may be received in at least one slot when the number of
slots is less than the number of the plurality of PUSCHs.
[0019] The resource allocation information may be transmitted to
the terminal through downlink control information (DCI) or radio
resource control (RRC) signaling.
[0020] The operation method may further comprise transmitting
resource allocation candidates of the plurality of PUSCHs to the
terminal through RRC signaling, wherein the resource allocation
information indicates one resource allocation candidate among the
resource allocation candidates, and the resource allocation
information is transmitted through DCI.
[0021] According to yet another exemplary embodiment of the present
disclosure, a terminal in a communication system may comprise a
processor and a memory storing at least one instruction executable
by the processor, wherein the at least one instruction may
configure the processor to receive, from a base station, resource
allocation information of a plurality of physical uplink shared
channels (PUSCHs) used for repetitive transmission of a same
transport block (TB); identify a position of each of the plurality
of PUSCHs in a time domain based on the resource allocation
information; and repeatedly transmit the same TB to the base
station at the position of each of the plurality of PUSCHs.
[0022] The resource allocation information may include information
indicating a start symbol of each of the plurality of PUSCHs,
information indicating a number of symbols constituting each of the
plurality of PUSCHs in the time domain, information indicating an
offset between a slot in which the resource allocation information
is transmitted and a slot to which at least one PUSCH among the
plurality of PUSCHs is allocated, and information indicating a
number of slots through which the plurality of PUSCHs are
transmitted.
[0023] A start symbol of at least one PUSCH among the plurality of
PUSCHs may be indicated by a symbol index or an offset between a
previous slot boundary and the start symbol.
[0024] One PUSCH may be transmitted in one slot when the number of
slots is equal to a number of the plurality of PUSCHs, and two or
more PUSCHs may be transmitted in at least one slot when the number
of slots is less than the number of the plurality of PUSCHs.
[0025] The at least one instruction may further configure the
processor to receive resource allocation candidates of the
plurality of PUSCHs from the base station through RRC signaling,
wherein the resource allocation information indicates one resource
allocation candidate among the resource allocation candidates, and
the resource allocation information is received through DCI.
[0026] According to the exemplary embodiments of the present
disclosure, each of the base station and the terminal can
repeatedly transmit the same transport block (TB) by using a
plurality of data channels (e.g., physical downlink shared channel
(PDSCH), physical uplink shared channel (PUSCH), physical sidelink
shared channel (PSSCH)). To this end, the base station can transmit
resource allocation information of the plurality of data channels
to the terminal through radio resource control (RRC) signaling
and/or downlink control information (DCI). In downlink
communication, the terminal can receive the same TB from the base
station through the plurality of data channels indicated by the
resource allocation information. In uplink communication, the
terminal can repeatedly transmit the same TB to the base station
through the plurality of data channels indicated by the resource
allocation information. Therefore, Ultra Reliable Low Latency
Communication (URLLC) requirements can be met, and the performance
of the communication system can be improved.
BRIEF DESCRIPTION OF DRAWINGS
[0027] Exemplary embodiments of the present disclosure will become
more apparent by describing in detail exemplary embodiments of the
present disclosure with reference to the accompanying drawings, in
which:
[0028] FIG. 1 is a conceptual diagram illustrating a first
embodiment of a communication system;
[0029] FIG. 2 is a block diagram illustrating a first embodiment of
a communication node constituting a communication system;
[0030] FIG. 3 is a timing diagram illustrating a first exemplary
embodiment of a method for repetitive transmission of a PUSCH in a
communication system;
[0031] FIG. 4A is a timing diagram illustrating a second exemplary
embodiment of a method for repetitive transmission of a PUSCH in a
communication system;
[0032] FIG. 4B is a timing diagram illustrating a third exemplary
embodiment of a method for repetitive transmission of a PUSCH in a
communication system;
[0033] FIG. 5A is a timing diagram illustrating a fourth exemplary
embodiment of a method for repetitive transmission of a PUSCH in a
communication system;
[0034] FIG. 5B is a timing diagram illustrating a fifth exemplary
embodiment of a method for repetitive transmission of a PUSCH in a
communication system;
[0035] FIG. 6 is a timing diagram illustrating a sixth exemplary
embodiment of a method for repetitive transmission of a PUSCH in a
communication system;
[0036] FIG. 7 is a timing diagram illustrating a seventh exemplary
embodiment of a method for repetitive transmission of a PUSCH in a
communication system;
[0037] FIG. 8 is a timing diagram illustrating a first exemplary
embodiment of a method for configuring configured grant resources
for repetitive transmission in a communication system;
[0038] FIG. 9A is a timing diagram illustrating an eighth exemplary
embodiment of a method for repetitive transmission of a PUSCH in a
communication system; and
[0039] FIG. 9B is a timing diagram illustrating a ninth exemplary
embodiment of a method for repetitive transmission of a PUSCH in a
communication system.
[0040] It should be understood that the above-referenced drawings
are not necessarily to scale, presenting a somewhat simplified
representation of various preferred features illustrative of the
basic principles of the disclosure. The specific design features of
the present disclosure, including, for example, specific
dimensions, orientations, locations, and shapes, will be determined
in part by the particular intended application and use
environment.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0041] While the present invention is susceptible to various
modifications and alternative forms, specific embodiments are shown
by way of example in the drawings and described in detail. It
should be understood, however, that the description is not intended
to limit the present invention to the specific embodiments, but, on
the contrary, the present invention is to cover all modifications,
equivalents, and alternatives that fall within the spirit and scope
of the present invention.
[0042] Although the terms "first," "second," etc. may be used
herein in reference to various elements, such elements should not
be construed as limited by these terms. These terms are only used
to distinguish one element from another. For example, a first
element could be termed a second element, and a second element
could be termed a first element, without departing from the scope
of the present invention. The term "and/or" includes any and all
combinations of one or more of the associated listed items.
[0043] It will be understood that when an element is referred to as
being "connected" or "coupled" to another element, it can be
directly connected or coupled to the other element or intervening
elements may be present. In contrast, when an element is referred
to as being "directly connected" or "directed coupled" to another
element, there are no intervening elements.
[0044] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
embodiments of the present invention. As used herein, the singular
forms "a," "an," and "the" are intended to include the plural forms
as well, unless the context clearly indicates otherwise. It will be
further understood that the terms "comprises," "comprising,"
"includes," and/or "including," when used herein, specify the
presence of stated features, integers, steps, operations, elements,
parts, and/or combinations thereof, but do not preclude the
presence or addition of one or more other features, integers,
steps, operations, elements, parts, and/or combinations
thereof.
[0045] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by those of ordinary skill in the art to which the
present invention pertains. It will be further understood that
terms defined in commonly used dictionaries should be interpreted
as having a meaning that is consistent with their meaning in the
context of the related art and will not be interpreted in an
idealized or overly formal sense unless expressly so defined
herein.
[0046] Hereinafter, exemplary embodiments of the present invention
will be described in greater detail with reference to the
accompanying drawings. To facilitate overall understanding of the
present invention, like numbers refer to like elements throughout
the description of the drawings, and description of the same
component will not be reiterated.
[0047] A communication system to which embodiments according to the
present disclosure will be described. The communication system may
be a 4G communication system (e.g., a long-term evolution (LTE)
communication system, an LTE-A communication system), a 5G
communication system (e.g. new radio (NR) communication system), or
the like. The 4G communication system can support communication in
a frequency band of 6 GHz or less, and the 5G communication system
can support communication in a frequency band of 6 GHz or less as
well as a frequency band of 6 GHz or more. The communication
systems to which embodiments according to the present disclosure
are applied are not restricted to what will be described below.
That is, the embodiments according to the present disclosure may be
applied to various communication systems. Here, the term
`communication system` may be used with the same meaning as the
term `communication network`, `LTE` may refer to `4G communication
system`, `LTE communication system`, or `LTE-A communication
system`, and `NR` may refer to `5G communication system` or `NR
communication system`.
[0048] FIG. 1 is a conceptual diagram illustrating a first
embodiment of a communication system.
[0049] Referring to FIG. 1, a communication system 100 may comprise
a plurality of communication nodes 110-1, 110-2, 110-3, 120-1,
120-2, 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6. Also, the
communication system 100 may further comprise a core network (e.g.,
a serving gateway (S-GW), a packet data network (PDN) gateway
(P-GW), a mobility management entity (MME), and the like. When the
communication system 100 is the 5G communication system (e.g., NR
system), the core network may include an access and mobility
management function (AMF), a user plane function (UPF), a session
management function (SMF), and the like.
[0050] The plurality of communication nodes 110 to 130 may support
communication protocols (e.g., LTE communication protocol, LTE-A
communication protocol, NR communication protocol, or the like).
The plurality of communication nodes 110 to 130 may support code
division multiple access (CDMA) technology, wideband CDMA (WCDMA)
technology, time division multiple access (TDMA) technology,
frequency division multiple access (FDMA) technology, orthogonal
frequency division multiplexing (OFDM) technology, filtered OFDM
technology, cyclic prefix OFDM (CP-OFDM) technology, discrete
Fourier transform-spread-OFDM (DFT-s-OFDM) technology, single
carrier FDMA (SC-FDMA) technology, non-orthogonal multiple access
(NOMA) technology, generalized frequency division multiplexing
(GFDM) technology, filter band multi-carrier (FBMC) technology,
universal filtered multi-carrier (UFMC) technology, space division
multiple access (SDMA) technology, or the like. Each of the
plurality of communication nodes may have the following
structure.
[0051] FIG. 2 is a block diagram illustrating a first embodiment of
a communication node constituting a communication system.
[0052] Referring to FIG. 2, a communication node 200 may comprise
at least one processor 210, a memory 220, and a transceiver 230
connected to the network for performing communications. Also, the
communication node 200 may further comprise an input interface
device 240, an output interface device 250, a storage device 260,
and the like. Each component included in the communication node 200
may communicate with each other as connected through a bus 270.
[0053] The processor 210 may execute a program stored in at least
one of the memory 220 and the storage device 260. The processor 210
may refer to a central processing unit (CPU), a graphics processing
unit (GPU), or a dedicated processor on which methods in accordance
with embodiments of the present disclosure are performed. Each of
the memory 220 and the storage device 260 may be constituted by at
least one of a volatile storage medium and a non-volatile storage
medium. For example, the memory 220 may comprise at least one of
read-only memory (ROM) and random access memory (RAM).
[0054] Referring again to FIG. 1, the communication system 100 may
comprise a plurality of base stations 110-1, 110-2, 110-3, 120-1,
and 120-2, and a plurality of terminals 130-1, 130-2, 130-3, 130-4,
130-5, and 130-6. Each of the first base station 110-1, the second
base station 110-2, and the third base station 110-3 may form a
macro cell, and each of the fourth base station 120-1 and the fifth
base station 120-2 may form a small cell. The fourth base station
120-1, the third terminal 130-3, and the fourth terminal 130-4 may
belong to cell coverage of the first base station 110-1. Also, the
second terminal 130-2, the fourth terminal 130-4, and the fifth
terminal 130-5 may belong to cell coverage of the second base
station 110-2. Also, the fifth base station 120-2, the fourth
terminal 130-4, the fifth terminal 130-5, and the sixth terminal
130-6 may belong to cell coverage of the third base station 110-3.
Also, the first terminal 130-1 may belong to cell coverage of the
fourth base station 120-1, and the sixth terminal 130-6 may belong
to cell coverage of the fifth base station 120-2.
[0055] Here, each of the plurality of base stations 110-1, 110-2,
110-3, 120-1 and 120-2 may refer to an NB (NodeB), an evolved NodeB
(eNB), a gNB, an advanced base station (ABS), a high reliability
base station (HR-BS), a base transceiver station (BTS), a radio
base station, a radio transceiver, an access point, an access node,
a radio access station (RAS), a mobile multihop relay base station
(MMR-BS), a relay station (RS), an advanced relay station (ARS), a
high reliability relay station (HR-RS), a home NodeB (HNB), a home
eNodeB (HeNB), a roadside unit (RSU), a radio remote head (RRH), a
transmission point (TP), a transmission and reception point (TRP),
or the like.
[0056] Each of the plurality of terminals 130-1, 130-2, 130-3,
130-4, 130-5 and 130-6 may refer to a user equipment (UE), a
terminal equipment (TE), an advanced mobile station (AMS), a high
reliability-mobile station (HR-MS), a terminal, an access terminal,
a mobile terminal, a station, a subscriber station, a mobile
station, a mobile subscriber station, a node, a device, an on board
unit (OBU), or the like.
[0057] Meanwhile, each of the plurality of base stations 110-1,
110-2, 110-3, 120-1, and 120-2 may operate in the same frequency
band or in different frequency bands. The plurality of base
stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to
each other via an ideal backhaul or a non-ideal backhaul, and
exchange information with each other via the ideal or non-ideal
backhaul. Also, each of the plurality of base stations 110-1,
110-2, 110-3, 120-1, and 120-2 may be connected to the core network
through the ideal or non-ideal backhaul. Each of the plurality of
base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may transmit a
signal received from the core network to the corresponding terminal
130-1, 130-2, 130-3, 130-4, 130-5, or 130-6, and transmit a signal
received from the corresponding terminal 130-1, 130-2, 130-3,
130-4, 130-5, or 130-6 to the core network.
[0058] Also, each of the plurality of base stations 110-1, 110-2,
110-3, 120-1, and 120-2 may support a multi-input multi-output
(MIMO) transmission (e.g., a single-user MIMO (SU-MIMO), a
multi-user MIMO (MU-MIMO), a massive MIMO, or the like), a
coordinated multipoint (CoMP) transmission, a carrier aggregation
(CA) transmission, a transmission in unlicensed band, a
device-to-device (D2D) communications (or, proximity services
(ProSe)), or the like. Here, each of the plurality of terminals
130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 may perform operations
corresponding to the operations of the plurality of base stations
110-1, 110-2, 110-3, 120-1, and 120-2 (i.e., the operations
supported by the plurality of base stations 110-1, 110-2, 110-3,
120-1, and 120-2). For example, the second base station 110-2 may
transmit a signal to the fourth terminal 130-4 in the SU-MIMO
manner, and the fourth terminal 130-4 may receive the signal from
the second base station 110-2 in the SU-MIMO manner. Alternatively,
the second base station 110-2 may transmit a signal to the fourth
terminal 130-4 and fifth terminal 130-5 in the MU-MIMO manner, and
the fourth terminal 130-4 and fifth terminal 130-5 may receive the
signal from the second base station 110-2 in the MU-MIMO
manner.
[0059] The first base station 110-1, the second base station 110-2,
and the third base station 110-3 may transmit a signal to the
fourth terminal 130-4 in the CoMP transmission manner, and the
fourth terminal 130-4 may receive the signal from the first base
station 110-1, the second base station 110-2, and the third base
station 110-3 in the CoMP manner. Also, each of the plurality of
base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may exchange
signals with the corresponding terminals 130-1, 130-2, 130-3,
130-4, 130-5, or 130-6 which belongs to its cell coverage in the CA
manner. Each of the base stations 110-1, 110-2, and 110-3 may
control D2D communications between the fourth terminal 130-4 and
the fifth terminal 130-5, and thus the fourth terminal 130-4 and
the fifth terminal 130-5 may perform the D2D communications under
control of the second base station 110-2 and the third base station
110-3.
[0060] Meanwhile, the communication system (e.g., NR communication
system) may support one or more services among the enhanced mobile
broadband (eMBB) service, the ultra-reliable and low-latency
communication (URLLC) service, and the massive machine type
communication (mMTC) service. Communication may be performed to
satisfy technical requirements of the services in the communication
system. In the URLLC service, the requirements of the transmission
reliability may be 1-10.sup.5, and the requirement of the uplink
and downlink user plane latency may be 0.5 ms.
[0061] Numerology applied to physical signals and channels in the
communication system may be varied. In a communication system to
which a cyclic prefix (CP) based OFDM waveform technique is
applied, the numerology may include a subcarrier spacing and a CP
length (or CP type). Table 1 may be a first embodiment of
numerologies for the CP-based OFDM. The subcarrier spacings may
have a relationship of a multiple of a power of two with each
other, and the CP length may be scaled at the same rate as the OFDM
symbol length. Depending on a frequency band in which the
communication system operates, a part of the numerologies in Table
1 may be supported. When the subcarrier spacing is 60 kHz, an
extended CP may be further supported.
TABLE-US-00001 TABLE 1 Subcarrier Spacing 15 kHz 30 kHz 60 kHz 120
kHz 240 kHz OFDM symbol 66.7 33.3 16.7 8.3 4.2 length (.mu.s) CP
length (.mu.s) 4.76 2.38 1.19 0.60 0.30
[0062] In the following description, a frame structure in the
communication system (e.g., NR communication system) will be
described. In the time domain, a building block may be a subframe,
a slot, and/or a minislot. The subframe may be used as a
transmission unit, and the length of the subframe may have a fixed
value (e.g., 1 ms) regardless of the subcarrier spacing. The slot
may comprise 14 consecutive OFDM symbols. The length of the slot
may be variable differently from the length of the subframe, and
may be inversely proportional to the subcarrier spacing. The slot
may be used as a scheduling unit and may be used as a configuration
unit of scheduling and hybrid automatic repeat request (HARQ)
timing.
[0063] The base station may schedule a data channel (e.g., physical
downlink shared channel (PDSCH) or physical uplink shared channel
(PUSCH)) using a part of the slot or the entire slot.
Alternatively, the base station may schedule a data channel using a
plurality of slots. The minislot may be used as a transmission
unit, and the length of the minislot may be set shorter than the
length of the slot. A slot having a length shorter than the length
of the conventional slot may be referred to as a `minislot` in the
communication system. A physical downlink control channel (PDCCH)
monitoring period and/or a duration of the data channel may be
configured to be shorter than the conventional slot, such that
minislot-based transmission can be supported.
[0064] The scalable numerology and/or minislot may be suitable for
transmission of a short transmission time interval (TTI) for URLLC.
For example, when a slot-based scheduling scheme is used, since the
length of the slot is inversely proportional to the subcarrier
spacing, the length of the TTI may be reduced by using a numerology
having a relatively large subcarrier spacing (e.g., 60 kHz). In
another example, when minislot-based scheduling scheme is used, the
length of the TTI may be reduced by allocating a data channel with
a relatively short duration (e.g., a data channel comprised of 2
symbols). In this case, for transmission of a control channel
including scheduling information of the data channel, the PDCCH
monitoring period of the terminal may be configured to be suitable
for the short TTI.
[0065] In the frequency domain, a building block may be a physical
resource block (PRB). One PRB may comprise 12 consecutive
subcarriers regardless of the subcarrier spacing. Thus, a bandwidth
occupied by one PRB may be proportional to the subcarrier spacing
of the numerology. The PRB may be used as a frequency-domain
resource allocation unit of the control channel and/or data channel
The minimum resource allocation unit of the downlink control
channel may be a control channel element (CCE). One CCE may include
one or more PRBs. The minimum resource allocation (e.g.,
bitmap-based resource allocation) unit of the data channel may be a
resource block group (RBG). One RBG may include one or more
PRBs.
[0066] A slot (e.g., slot format) may be composed of a combination
of one or more of downlink duration, flexible duration or unknown
duration (hereinafter collectively referred to as `flexible
duration`), and an uplink duration. Each of the downlink duration,
the flexible duration, and the uplink duration may be comprised of
one or more consecutive symbols. The flexible duration may be
located between the downlink duration and the uplink duration,
between a first downlink duration and a second downlink duration,
or between a first uplink duration and a second uplink duration.
When the flexible duration is inserted between the downlink
duration and the uplink duration, the flexible duration may be used
as a guard period. One slot may include a plurality of flexible
durations. Alternatively, one slot may not include a flexible
duration. The terminal may perform a predefined operation or an
operation configured by the base station semi-statically or
periodically (e.g., a PDCCH monitoring operation, a synchronization
signal / physical broadcast channel (SS/PBCH) block reception and
measurement operation, a channel state information-reference signal
(CSI-RS) reception and measurement operation, a downlink
semi-persistent scheduling (SPS) PDSCH reception operation, a
sounding reference signal (SRS) transmission operation, a physical
random access channel (PRACH) transmission operation, a
periodically-configured PUCCH transmission operation, a PUSCH
transmission operation according to a configured grant, or the
like) in the corresponding flexible duration until the
corresponding flexible duration is overridden to be a downlink
duration or an uplink duration. Alternatively, the terminal may not
perform any operation in the corresponding flexible duration until
the corresponding flexible duration is overridden to be a downlink
duration or an uplink duration.
[0067] The slot format may be configured semi-statically by higher
layer signaling (e.g. radio resource control (RRC) signaling).
Information indicating a semi-static slot format may be included in
system information, and the semi-static slot format may be
configured in a cell-specific manner. In addition, the slot format
may be additionally configured for each terminal through
UE-specific higher layer signaling (e.g., RRC signaling). The
flexible duration of the slot format configured in the
cell-specific manner may be overridden by the UE-specific higher
layer signaling to a downlink duration or an uplink duration. Also,
the slot format may be dynamically indicated by a slot format
indicator (SFI) included in downlink control information (DCI).
[0068] The terminal may perform most of downlink and uplink
operations in a bandwidth part. The bandwidth part may be defined
as a set of consecutive PRBs in the frequency domain. Only one
numerology may be used for transmission of a control channel or a
data channel in one bandwidth part. The terminal performing an
initial access procedure may obtain configuration information of an
initial bandwidth part from the base station through system
information. A terminal operating in an RRC connected state may
obtain the configuration information of the bandwidth part from the
base station through UE-specific higher layer signaling.
[0069] The configuration information of the bandwidth part may
include a numerology (e.g., a subcarrier spacing and a CP length)
applied to the bandwidth part. Also, the configuration information
of the bandwidth part may further include information indicating a
position of a starting PRB of the bandwidth part and information
indicating the number of PRBs constituting the bandwidth part. At
least one bandwidth part of the bandwidth part(s) configured to the
terminal may be activated. For example, within one carrier, one
uplink bandwidth part and one downlink bandwidth part may be
activated respectively. In a time division duplex (TDD) based
communication system, a pair of one uplink bandwidth part and one
downlink bandwidth part may be activated. If a plurality of
bandwidth parts are configured for the terminal within one carrier,
the active bandwidth part of the terminal may be switched.
[0070] The minimum resource unit constituting the PDCCH may be a
resource element group (REG). The REG may be composed of one PRB
(e.g., 12 subcarriers) in the frequency domain and one OFDM symbol
in the time domain. Thus, one REG may include 12 resource elements
(REs). In the OFDM-based communication system, an RE may be a
minimum physical resource unit composed of one subcarrier and one
OFDM symbol. A demodulation reference signal (DMRS) for
demodulating the PDCCH may be mapped to 3 REs among 12 REs
constituting the REG, and control information (e.g., modulated DCI)
may be mapped to the remaining 9 REs.
[0071] One PDCCH candidate may be composed of one CCE or aggregated
CCEs. One CCE may be composed of a plurality of REGs. In the
embodiments, a CCE aggregation level may be referred to as L, and
the number of REGs constituting one CCE may be referred to as K.
The communication system (e.g., NR communication system) may
support `K=6, L=1, 2, 4, 8 or 16`. The higher the CCE aggregation
level, the more physical resources may be used for transmission of
a PDCCH. In this case, by using a low code rate for the PDCCH
transmission, the reception performance of the PDCCH can be
improved.
[0072] A control resource set (CORESET) may be a resource region in
which the terminal performs a blind decoding on PDCCHs. The CORESET
may be composed of a plurality of REGs. The CORESET may consist of
one or more PRBs in the frequency domain and one or more symbols
(e.g., OFDM symbols) in the time domain. The symbols constituting
one CORESET may be consecutive in the time domain. The PRBs
constituting a single CORESET may be continuous or discontinuous in
the frequency domain. One DCI (e.g., one PDCCH) may be transmitted
within one CORESET or one search space logically associated with
the CORESET. Multiple CORESETs may be configured with respect to a
cell and a terminal, and the CORESETs may overlap each other.
[0073] The CORESET may be configured to the terminal by a PBCH
(e.g., system information transmitted through the PBCH). The ID of
the CORESET configured by the PBCH may be 0. That is, the CORESET
configured by the PBCH may be referred to as a CORESET #0. A
terminal operating in an RRC idle state may perform a monitoring
operation in the CORESET #0 in order to receive a first PDCCH in
the initial access procedure. Not only terminals operating in the
RRC idle state but also terminals operating in the RRC connected
state may perform monitoring operations in the CORESET #0. The
CORESET may be configured to the terminal by other system
information (e.g., system information block type 1 (SIB1)) other
than the system information transmitted through the PBCH. For
example, for reception of Msg2 and Msg4 in a random access
procedure, the terminal may receive the SIB1 including the
configuration information of the CORESET. Also, the CORESET may be
configured to the terminal by UE-specific higher layer signaling
(e.g., RRC signaling).
[0074] In each downlink bandwidth part, one or more CORESETs may be
configured for the terminal. Here, a case that the CORESET is
configured in the bandwidth part means that the CORESET is
logically associated with the bandwidth part and the terminal
monitors the corresponding CORESET in the bandwidth part. The
initial downlink active bandwidth part may include the CORESET #0
and may be associated with the CORESET #0. The CORESET #0 having a
quasi-co-location (QCL) relationship with an SS/PBCH block may be
configured for the terminal in a primary cell (PCell), a secondary
cell (SCell), and a primary secondary cell (PSCell). In the
secondary cell (SCell), the CORESET #0 may not be configured for
the terminal.
[0075] The terminal may receive a PDCCH using a blind decoding
scheme. A search space may be a set of candidate resource regions
through which a PDCCH can be transmitted. The terminal may perform
a blind decoding on each of the PDCCH candidates within a search
space which is predefined or configured by the base station. The
terminal may determine whether a PDCCH is transmitted to itself by
performing a cyclic redundancy check (CRC) on a blind decoding
result. When it is determined that a PDCCH is a PDCCH for the
terminal itself, the terminal may receive the PDCCH.
[0076] A PDCCH candidate constituting the search space may consist
of CCEs selected by a predefined hash function within an occasion
of the CORESET or the search space. The search space may be defined
and configured for each CCE aggregation level. In this case, a set
of search spaces for all CCE aggregation levels may be referred to
as a `search space set`. In the embodiments, `search space` may
mean `search space set`, and `search space set` may mean `search
space`.
[0077] A search space set may be logically associated with a single
CORESET. One CORESET may be logically associated with one or more
search space sets. A common search space set configured through the
PBCH may be used to monitor a DCI scheduling a PDSCH for
transmission of the SIB1. The ID of the common search space set
configured through the PBCH may be set to 0. That is, the common
search space set configured through the PBCH may be defined as a
type 0 PDCCH common search space set or a search space set #0. The
search space set #0 may be logically associated with the CORESET
#0.
[0078] The search space set may be classified into a common search
space set and a UE-specific search space set. A common DCI may be
transmitted in the common search space set, and a UE-specific DCI
may be transmitted in the UE-specific search space set. Considering
degree of freedom in scheduling and/or fallback transmission,
UE-specific DCIs may also be transmitted in the common search space
set. For example, the common DCI may include resource allocation
information of a PDSCH for transmission of system information,
paging, power control commands, slot format indicator (SFI),
preemption indicator, and the like. The UE-specific DCI may include
PDSCH resource allocation information, PUSCH resource allocation
information, and the like. A plurality of DCI formats may be
defined according to the payload and the size of the DCI, the type
of radio network temporary identifier (RNTI), or the like.
[0079] In the exemplary embodiments, the common search space may be
referred to as a `CSS`, and the common search space set may be
referred to as a `CSS set`. Also, in the exemplary embodiments, the
UE-specific search space may be referred to as a `USS`, and the
UE-specific search space set may be referred to as a `USS set`.
[0080] Meanwhile, since a communication system (e.g., NR
communication system) can support a wide frequency band of 0 to 100
GHz, a method of operating beams in a high frequency band may be
different from that of a low frequency band. Since a single path
loss due to a channel is relatively small in the low frequency band
(e.g., the band below 6 GHz), the signal may be transmitted and
received using a beam having a wide beamwidth. In particular, even
when a control channel is transmitted using a single beam, the
control channel may be transmitted throughout a cell or a sector.
That is, the entire cell or the entire sector can be covered by a
single beam.
[0081] On the other hand, since a signal path loss due to a channel
is relatively large in the high frequency band (e.g., the band
above 6 GHz), the signal may be transmitted in a beamforming scheme
using a plurality of antennas. For extension of cell coverage or
terminal coverage, not only data channels but also common signals
and control channels may be transmitted in a beamforming scheme. In
this case, when a beam having a narrow beamwidth is formed through
a plurality of antennas, a signal may be transmitted several times
using beams in different directions to cover the entire cell or the
entire sector. The operation in which the beamformed signal is
transmitted several times through different resources in the time
domain may be referred to as a beam sweeping operation. A system
for transmitting signals using beams having a narrow beamwidth may
be referred to as a multi-beam system.
[0082] Beam management may be required in the multi-beam system. In
this case, the terminal may measure quality of a beam by receiving
a specific reference signal (e.g., reference signal (RS) for beam
management or RS for beam failure detection), and report
information indicating one or more beams of good quality to the
base station. For example, the terminal may calculate a reference
signal received power (RSRP) for each of the beams and report to
the base station information indicating the best beam in terms of
RSRP (e.g., beam quality information). The base station may
determine a beam to be used for transmission of a physical signal
or channel based on the beam quality information received from the
terminal, and may configure one or more transmission configuration
information (TCI) states for a physical channel (e.g., PDCCH and
PDSCH) in the terminal.
[0083] The TCI state may include an ID of a reference signal having
a QCL relationship with a DMRS of the physical channel to which the
TCI is applied and/or a QCL type. The QCL may include a spatial
QCL. A case that a spatial QCL for a channel and/or a reference
signal is established may mean that the terminal can assume the
same reception beam (e.g., analog reception beam), the same
reception channel spatial correlation, and the like for the
corresponding channel and/or reference signal. The reception beam
and the reception channel spatial correlation may be referred to as
a spatial reception (RX) parameter. In addition to the spatial QCL,
channel characteristics such as delay spread, Doppler spread,
Doppler shift, average gain, and average delay may be configured as
a QCL by configuring a TCI state. In the embodiments, the QCL may
refer to a general QCL or spatial QCL. In the NR communication
system, the spatial QCL may correspond to QCL-TypeD.
[0084] Hereinafter, methods for transmitting and receiving data
channels in the communication system will be described. Even when a
method (e.g., transmission or reception of a signal) to be
performed at a first communication node among communication nodes
is described, a corresponding second communication node may perform
a method (e.g., reception or transmission of the signal)
corresponding to the method performed at the first communication
node. That is, when an operation of a terminal is described, a
corresponding base station may perform an operation corresponding
to the operation of the terminal. Conversely, when an operation of
the base station is described, the corresponding terminal may
perform an operation corresponding to the operation of the base
station.
[0085] The exemplary embodiments below relate to methods for
repetitive transmission of a data channel to ensure the
requirements of the URLLC service (e.g., high transmission
reliability). The following exemplary embodiments may be applied to
various wireless communication systems as well as the NR
communication system.
[0086] A plurality of HARQ processes may be performed in a
communication system. For example, up to 16 HARQ processes may be
performed for each of uplink and downlink in the NR communication
system. The HARQ process(es) may be managed by an HARQ entity. When
a plurality of carriers are aggregated for a terminal, the HARQ
entity may be operated for each carrier, and the plurality of HARQ
processes may be performed for each carrier.
[0087] Data that the base station or the terminal desires to
transmit may be managed in units of a transport block (TB) or a
medium access control (MAC) protocol data unit (PDU) by each HARQ
process. In downlink communication, a TB or MAC PDU may be
transmitted from the base station to the terminal through a data
channel In this case, the TB or MAC PDU may include a downlink
shared channel (DL-SCH) and/or a MAC control element (CE). In
uplink communication, a TB or MAC PDU may be transmitted from the
terminal to the base station through a data channel In this case,
the TB or MAC PDU may include an uplink shared channel (UL-SCH), a
MAC CE, and/or physical layer control information (e.g., uplink
control information (UCI)). The data channel may include a downlink
data channel (e.g., physical downlink shared channel (PDSCH)), an
uplink data channel (e.g., physical uplink shared channel (PUSCH)),
and a sidelink data channel (e.g., physical sidelink shared channel
(PSSCH)).
[0088] When a dynamic scheduling scheme is used, scheduling
information of a data channel may be included in a DCI. The DCI may
be transmitted to the terminal through a PDCCH. When a semi-static
scheduling scheme is used, scheduling information of a data channel
may be configured to the terminal through RRC signaling. The
scheduling information of the data channel may be transmitted to
the terminal using at least one of RRC signaling, DCI, and a MAC
CE. For example, a part of the scheduling information (e.g.,
transmission configuration information (TCI) state information) of
the data channel may be indicated to the terminal through a MAC
CE.
[0089] [Repetitive Transmission Method of Data Channel]
[0090] The data channels corresponding to the same HARQ process may
be repeatedly transmitted. In this case, one transmission in the
repeated transmission procedure of the data channel may be referred
to as an `instance`. For example, each PDSCH transmission may be
referred to as a `PDSCH instance` when the PDSCH is repeatedly
transmitted, each PUSCH transmission may be referred to as a `PUSCH
instance` when the PUSCH is repeatedly transmitted, and each PSSCH
transmission may be referred to as a `PSSCH instance` when the
PSSCH is repeatedly transmitted. Each `instance` of a data channel
may mean each transmission occasion of the data channel. Each
`instance` of a data channel may also be referred to as the data
channel. For example, a case that a PUSCH is transmitted in a slot
may mean that a PUSCH instance is transmitted in the corresponding
slot.
[0091] The instances constituting repetitive transmission of the
data channel may correspond to the same HARQ process and may
include coded data for the same TB(s). In the following exemplary
embodiments, `repetitive transmission of a data channel` may mean
`repetitive transmission for the same HARQ process and the same
TB(s)`. The following exemplary embodiments may be applied to other
data channels (e.g., PSSCH) as well as PDSCH and PUSCH. For
example, the following exemplary embodiments defining a PUSCH
transmission method may be applied also to PDSCH and PSSCH
transmission. In addition, the following exemplary embodiments
defining the PUSCH transmission method relate to a communication
method between a base station and a terminal, but the PSSCH
transmission method to which the following exemplary embodiments
are applied may be understood as a communication method between a
terminal and another terminal.
[0092] The data channel (e.g., PDSCH, PUSCH, or PSSCH) may be
repeatedly transmitted in a plurality of slots. There may be one
data channel instance in each slot, and time and frequency
resources for the data channel instance may be equally allocated in
each slot. Each data channel instance may be mapped to contiguous
symbol(s) in the time domain.
[0093] FIG. 3 is a timing diagram illustrating a first exemplary
embodiment of a method for repetitive transmission of a PUSCH in a
communication system.
[0094] Referring to FIG. 3, two consecutive slots may be
aggregated, and the terminal may transmit a PUSCH in each slot. For
example, the terminal may transmit the first PUSCH instance to the
base station through a slot n, and may transmit the second PUSCH
instance to the base station through a slot n+1. The time resources
(e.g., eleventh to fourteenth symbols) allocated for the first
PUSCH instance in the slot n may be the same as the time resources
(e.g., eleventh to fourteenth symbols) allocated for the second
PUSCH instance in the slot n+1. The frequency resources allocated
for the first PUSCH instance in the slot n (e.g., frequency region
A) may be the same as the frequency resources allocated for the
second PUSCH instance in the slot n+1 (e.g., frequency region
A).
[0095] Time and frequency domain resource allocation information of
the PUSCH instance may be indicated to the terminal through an
uplink (UL) grant transmitted through a PDCCH. The time and
frequency domain resource allocation information indicated through
the uplink grant may be one of resource allocation candidate(s)
preconfigured to the terminal by RRC signaling. The uplink grant in
the NR communication system may be defined as a DCI format 0_x
(x=0, 1, 2, . . . ). Here, it may be assumed that the terminal has
a capability for transmitting a PUSCH after two symbols from a
reception completion time of the uplink grant.
[0096] In addition to the same resource allocation information, the
same scheduling (e.g., modulation and coding scheme (MCS), number
of transmission layers, etc.) may be applied to the PUSCH
instances. When PUSCH repetitive transmission is applied, the
number of transmission layers may be limited to one. The redundancy
version (RV) applied to each of the PUSCH instances may be
identical or different. When a different RV is applied to each of
the PUSCH instances, error correction capability by channel coding
may be improved.
[0097] Meanwhile, in a communication system supporting the URLLC
services, high transmission reliability and low latency can be
guaranteed. Thus, sufficient time-frequency resources may be
allocated for the control and/or data channel Also, a time required
for transmission in a wireless section may be short enough. In
order to satisfy the URLLC requirements in the exemplary embodiment
shown in FIG. 3, it may be assumed that at least eight symbols are
allocated for the PUSCH, and the transmission timing of the uplink
grant and the transmission start timing of the PUSCH in the slot n
may be the earliest timing that the base station can schedule on
the basis of the dynamic grant. In this case, since four uplink
symbols are available for PUSCH transmission in the slot n, the
base station may repeatedly transmit the PUSCH of the same TB in
the slot n+1. That is, the base station may allocate additional
symbols (e.g., four symbols) to the slot n+1 for the PUSCH
transmission. However, since the positions (e.g., eleventh to
fourteenth) of the symbols where the PUSCH instances are
transmitted in the respective slots are the same, a transmission
delay of the PUSCH may increase.
[0098] FIG. 4A is a timing diagram illustrating a second exemplary
embodiment of a method for repetitive transmission of a PUSCH in a
communication system, and FIG. 4B is a timing diagram illustrating
a third exemplary embodiment of a method for repetitive
transmission of a PUSCH in a communication system.
[0099] As shown in FIGS. 4A and 4B, the position of time resources
allocated for the first PUSCH instance in the slot n may be
different from the position of time resources allocated for the
second PUSCH instance in the slot n+1. In the exemplary embodiment
shown in FIG. 4A, the first to fourth symbols of the slot n+1 may
be allocated for the second PUSCH instance, and in the exemplary
embodiment shown in FIG. 4B, the fourth to sixth symbols of the
slot n+1 may be allocated for the second PUSCH instance.
[0100] The amount of resources used for transmission of the same TB
in the exemplary embodiment shown in FIG. 4A may be the same as the
amount of resources used for transmission of the same TB in the
exemplary embodiment shown in FIG. 3. In the exemplary embodiment
shown in FIG. 4A, a transmission completion time point of the same
TB may be earlier by 10 symbols than the transmission completion
time point of the same TB in the exemplary embodiment shown in FIG.
3. The amount of resources used for transmission of the same TB in
the exemplary embodiment shown in FIG. 4B may be less than the
amount of resources used for transmission of the same TB in the
exemplary embodiment shown in FIG. 3. In the exemplary embodiment
shown in FIG. 4B, a transmission completion time point of the same
TB may be earlier by 7 symbols than the transmission completion
time point of the same TB in the exemplary embodiment shown in FIG.
3.
[0101] Depending on a slot format configuration, uplink
signal/channel configuration, and the like, a duration of symbols
in which PUSCH can be transmitted in each slot may be different.
Thus, as in the exemplary embodiments shown in FIGS. 4A and 4B, if
the relative in-slot positions of the time resources and/or the
numbers of symbols allocated for PUSCH instances are different, the
transmission latency may be reduced and the transmission
reliability may be improved. The method shown in FIG. 4A and/or
FIG. 4B may be referred to as `Method 100`. In the following
exemplary embodiments, the number of repetitive transmissions of a
data channel (e.g., PDSCH, PUSCH, or PSSCH) for the same TB may be
defined as K. For example, K may correspond to the number of PUSCH
instances scheduled by one DCI (e.g., uplink grant).
[0102] As specific methods of Method 100, `Method 110` and `Method
120` may be considered. In Method 110, a plurality of data channel
instances may be regarded as one data channel (e.g., PDSCH, PUSCH,
or PSSCH), and resource allocation information for one data channel
may be configured. For example, the base station may inform the
terminal of time domain resource allocation information for one
PUSCH. The time domain resource allocation information for a PUSCH
may include at least one of information indicating a start slot of
the PUSCH (e.g., a slot offset between a reception time point
(e.g., reception completion time point) of a PDCCH including an
uplink grant and a transmission start time point of the PUSCH),
information indicating a start symbol of the PUSCH, and information
indicating a duration of the PUSCH (e.g., information indicating
the number of consecutive symbols constituting the PUSCH). In
addition, the time domain resource allocation information for one
PUSCH may further include information (e.g., K) indicating the
number of repetitive transmissions of the PUSCH.
[0103] The start symbol and the duration of the PUSCH may be
represented by a single value (e.g., a start and length indicator
value (SLIV)). When the index of the start symbol of the PUSCH is S
and the duration of the PUSCH is L, the SLIV may be defined as in
Equation 1 below. The index of the s-th symbol in the slot may be
`s-1`. For example, the index of the eleventh symbol in the slot
may be 10. In the NR communication system, `0.ltoreq.S.ltoreq.13`
may be defined when a normal cyclic prefix (CP) is used, and
`0.ltoreq.S.ltoreq.11` may be defined when an extended CP is
used.
If (L-1).ltoreq.7, then
SLIV=14.times.(L-1)+S
Else
SLIV=14.times.(14-L+1)+(14-1-S)
Where 0<L.ltoreq.14-S [Equation 1]
[0104] In addition, the time domain resource allocation information
for the PUSCH may further include information indicating a PUSCH
mapping type. The PUSCH mapping type may indicate type A or type B.
The terminal may identify the PUSCH mapping type by receiving the
time domain resource allocation information from the base station.
When the PUSCH mapping type A is applied in the communication
system, the position of the first symbol of the DM-RS for
demodulating the PUSCH may be semi-statically configured by RRC
signaling (e.g., master information block (MIB) or cell-specific
RRC signaling). Here, the position of the first symbol of the DM-RS
may be configured based on a slot boundary as a reference time
point. When the PUSCH mapping type B is applied in the
communication system, the position of the first symbol of the DM-RS
for demodulating the PUSCH may generally be the start symbol of the
PUSCH. Alternatively, exceptionally, the position of the first
symbol of the DM-RS may be another symbol except the start symbol
of the PUSCH.
[0105] The valid ranges of S and L according to the PUSCH mapping
type and the CP type may follow Table 2. Alternatively, the valid
ranges of S and L may be extended. For example, if a sum of S and L
exceeds 14, the corresponding values of S and L may be defined. The
time domain resource allocation information of PDSCH may be
configured the same as or similar to the above-described time
domain resource allocation information of PUSCH.
TABLE-US-00002 TABLE 2 PUSCH mapping Normal CP Extended CP type S L
S + L S L S + L Type A 0 {4, . . . , 14} {4, . . . , 14} 0 {4, . .
. , 12} {4, . . . , 12} Type B {0, . . . , 13} {1, . . . , 14} {1,
. . . , 14} {0, . . . , 12} {1, . . . , 12} {1, . . . , 12}
[0106] Meanwhile, the start symbol S of the PUSCH may be
represented by a symbol offset from a PDCCH scheduling the PUSCH.
When the PDCCH occupies a plurality of symbols, the symbol offset
may be defined based on one symbol among the plurality of symbols.
For example, S may be defined as an offset between the start symbol
or end symbol of the PDCCH and the start symbol of the PUSCH. In
the exemplary embodiments shown in FIGS. 4A and 4B, S may be 3.
[0107] The exemplary embodiments shown in FIGS. 4A and 4B may be
performed by Method 110. In the embodiment illustrated in FIG. 4A,
when Method 110 is applied, the time domain resource allocation
information for one PUSCH may include at least one of information
indicating that a start slot of the PUSCH is n, information
indicating that a slot offset between a PDCCH including an uplink
grant and the PUSCH is 0, and information indicating that (S, L) is
(10, 8). Each of S and L may be transmitted to the terminal.
Alternatively, S and L may be transmitted to the terminal in the
SLIV form. The above-described signaling methods for S and L may be
equally applied in the following exemplary embodiments.
[0108] In the embodiment illustrated in FIG. 4A, when Method 110 is
applied, the time domain resource allocation information for one
PUSCH may include at least one of information indicating that a
start slot of the PUSCH is n, information indicating that a slot
offset between a PDCCH including an uplink grant and the PUSCH is
0, and information indicating that (S, L) is (10, 7).
[0109] In addition, when Method 110 is applied, even though the
PUSCH is actually mapped to a plurality of slots, the base station
may configure the number of slots aggregated for PUSCH transmission
or a parameter (e.g., the number of PUSCH instances, K, aggregation
factor, etc.) corresponding to the number of slots to be 1, and
inform the configured value to the terminal. In the following
exemplary embodiments, `the number of slots aggregated for PUSCH
transmission`, `the number of PUSCH instances`, K, and `aggregation
factor` may be collectively referred to as `the number of slots
aggregated for PUSCH transmission`. The aggregation factor may be
aggregationFactorUL which is an RRC parameter in uplink
communication. The aggregation factor may be aggregationFactorDL
which is an RRC parameter in downlink communication.
[0110] In the exemplary embodiments shown in FIGS. 4A and 4B, even
when two PUSCH instances are scheduled in two consecutive slots
from a terminal perspective, the base station may inform the
terminal of time domain resource allocation information for one
PUSCH. Also, the base station may transmit an RRC parameter (e.g.,
aggregationFactorUL) and/or a DCI indicating that the number of
slots aggregated for PUSCH transmission is 1 to the terminal. The
above-described time domain resource allocation information may be
configured (e.g., indicated) to the terminal through DCI and/or RRC
signaling.
[0111] When D valid symbol(s) in which the first PUSCH instance can
be transmitted is defined as a `first valid symbol set`, L may be
less than or equal to D in Method 110. In this case, the terminal
may transmit the PUSCH using L symbols from the first symbol among
the
[0112] D valid symbols. In contrast, L may exceed D in Method 110.
In this case, the terminal may transmit the first PUSCH instance
using D valid symbols from the start slot of the PUSCH. The
terminal may transmit PUSCH data corresponding to the remaining
(L-D) symbols in valid symbol(s) of the next (or subsequent)
slot(s). In the exemplary embodiments shown in FIGS. 4A and 4B, the
first valid symbol set may be the eleventh to fourteenth symbols of
the slot n. In this case, the first valid symbol set may include
the start symbol of the PUSCH to the end symbol of the slot. All
symbols from the start symbol of the PUSCH to the end symbol of the
slot may not be downlink symbols. Here, a transmission direction
(e.g., uplink or downlink) of a symbol may be determined according
to a semi-static slot format configuration scheme.
[0113] Alternatively, a transmission direction of a symbol may be
determined by a combination of a semi-static slot format
configuration scheme and a dynamic slot format indication scheme. A
dynamic slot format may include slot formats (e.g., SFI #46 to #55)
in which at least one downlink symbol exists after flexible symbols
or uplink symbols within one slot. In this case, the first valid
symbol set may be a set of uplink symbol(s) and flexible symbol(s)
consecutive from the start symbol of the PUSCH. If there is another
continuous uplink and/or flexible duration even after the first
valid symbol set in the start slot of the PUSCH, the terminal may
transmit the PUSCH data corresponding to the remaining (L-D)
symbols in the continuous uplink and/or flexible duration within an
allowable range. That is, the terminal may transmit a plurality of
PUSCH instances in one slot.
[0114] A valid symbol set (e.g., valid symbol(s) after the first
valid symbol set in the start slot of the PUSCH and/or valid
symbol(s) in the next slot(s)) for transmitting the remaining (L-D)
symbols may be determined according to a slot format configuration
scheme. For example, the valid symbol set in the next slot may be
one or more of the flexible symbol(s) and uplink symbol(s)
configured by the semi-static slot format configuration scheme. The
terminal may transmit the next PUSCH instance using consecutive
symbol(s) from the first symbol in the next valid symbol set. This
may be referred to as `Method 111`.
[0115] In the exemplary embodiment shown in FIG. 4A, when the slot
n+1 is an uplink slot, all symbols of the slot n+1 may be valid
symbols. Accordingly, the terminal may transmit the second PUSCH
instance in four symbols (e.g., first to fourth symbols)
consecutive from the first symbol in the slot n+1. In the exemplary
embodiment shown in FIG. 4B, the first to third symbols of the slot
n+1 may be downlink symbols, the fourth to fifth symbols of the
slot n+1 may be flexible symbols, and the remaining symbols (e.g.,
sixth to fourteenth symbols) of the slot n+1 may be uplink symbols.
In this case, the fourth to fourteenth symbols of the slot n+1 may
be valid symbols. Accordingly, the terminal may transmit the second
PUSCH instance in the fourth to sixth symbols of the slot n+1.
Method 111 may have excellent performance in terms of transmission
latency of the PUSCH, but according to Method 111, scheduling
flexibility may be reduced.
[0116] FIG. 5A is a timing diagram illustrating a fourth exemplary
embodiment of a method for repetitive transmission of a PUSCH in a
communication system. The PUSCH scheduling scheme in FIG. 5A may be
the same as the PUSCH scheduling scheme in FIG. 4B.
[0117] Referring to FIG. 5A, the first to third symbols of the slot
n+1 may be downlink symbols, the fourth to fifth symbols of the
slot n+1 may be flexible symbols, and the remaining symbols (e.g.,
sixth to fourteenth symbols) of the slot n+1 may be uplink symbols.
According to Method 111, the second PUSCH instance may be
transmitted in the fourth to sixth symbols of the slot n+1. In this
case, a PDSCH may be scheduled in the second to third symbols of
the slot n+1. When the PDSCH and the PUSCH are scheduled for the
same terminal in the slot n+1, the terminal may not perform one of
the reception operation of the PDSCH and the transmission operation
of the PUSCH.
[0118] In order to resolve this problem, the terminal may regard
the scheduling in which the downlink transmission and the uplink
transmission overlap as an error, and may not expect the downlink
transmission to overlap with the uplink transmission.
Alternatively, when the downlink transmission and the uplink
transmission overlap, the terminal may consider that a transmission
scheduled first among the downlink transmission and the uplink
transmission is valid or, conversely, that a late scheduled
transmission is valid. Alternatively, the terminal may defer the
start time of the next PUSCH instance(s) (e.g., second PUSCH
instance). This may be referred to as `Method 112`.
[0119] In addition, the terminal may determine the start symbol of
the second PUSCH instance as a later symbol among the start symbol
according to Method 111 and a symbol after a predetermined time
from the reception completion time of the downlink channel (e.g.,
PDSCH), and may transmit the next PUSCH instance(s) (e.g., second
PUSCH) from the determined symbol. This may be referred to as
`Method 113`. The predetermined time may be configured in unit of
symbol(s). The base station may inform the terminal of the
predetermined time.
[0120] On the other hand, when the receiving terminal of the PDSCH
and the transmitting terminal of the PUSCH are different in the
slot n+1, the second PUSCH instance may act as interference to the
PDSCH. In order to allow scheduling of the PDSCH and to prevent
interference between the PDSCH and the second PUSCH instance,
Method 112 may be used.
[0121] FIG. 5B is a timing diagram illustrating a fifth exemplary
embodiment of a method for repetitive transmission of a PUSCH in a
communication system. For example, FIG. 5B illustrates a repetitive
transmission method of a PUSCH according to Method 112 or Method
113.
[0122] Referring to FIG. 5B, the terminal may delay and transmit
the second PUSCH instance by one symbol. The time offset for Method
112 or Method 113 may be configured semi-statically by RRC
signaling. Alternatively, the time offset may be dynamically
configured by DCI (e.g., uplink grant scheduling the PUSCH).
Alternatively, the time offset may be configured by a combination
of RRC signaling and DCI.
[0123] Since the number of symbols required for switching from the
downlink communication to the uplink communication may vary
according to a frequency band and a numerology, the time offset may
be configured differently according to the frequency band and/or
the numerology. The time offset may be configured for each carrier
or bandwidth part (BWP). The time offset for repetitive PUSCH
transmission according to a configured grant may be separately
configured. When the number of repeated PUSCH instances is 3 or
more, the time offset may be applied to the remaining PUSCH
instances except the first PUSCH instance. The same time offset may
be applied to a plurality of PUSCH instances.
[0124] Method 112 or Method 113 may be applied not only to the
above-described exemplary embodiments but also to an exemplary
embodiment in which symbol positions or start symbol positions of
some PUSCH instances constituting the PUSCH repetitive transmission
are determined by an implicit scheme. Method 110 may be one
exemplary embodiment of the PUSCH repetitive transmission method,
and Method 111 may be one exemplary embodiment in which the
position of the start symbol of the PUSCH instance is implicitly
determined.
[0125] Since the signaling scheme for the existing single slot
based PUSCH scheduling is reused in Method 110, overhead of RRC
signaling and/or DCI may be maintained. Or, the overhead of RRC
signaling and/or DCI may increase by a minimum. However, various
slot formats may be supported in a TDD band, and various
configurations of uplink signals and channels (e.g., PUSCH,
physical uplink control channel (PUCCH), SRS, PRACH, and the like)
of the same terminal or different terminals may exist. In such
environment, it may be difficult to generalize valid symbol
determination rules considering multiplexing.
[0126] Thus, only with the existing signaling schemes or some
improved methods (e.g., Method 112, Method 113, and the like), it
may be difficult for the base station to schedule PUSCH instances
in desired slot and symbol positions. `Method 120` below may be
used to resolve this problem.
[0127] In Method 120, the base station may inform the terminal of
resource allocation information for a plurality of PUSCH instances.
For example, the base station may signal time domain resource
allocation information for each PUSCH instance to the terminal. In
this case, unlike Method 110, the base station may inform the
terminal of information indicating the number of slots aggregated
for the PUSCH transmission. For example, in the exemplary
embodiments shown in FIGS. 4A and 4B, when two PUSCH instances are
scheduled in two consecutive slots, the base station may transmit
to the terminal an RRC parameter (e.g., aggregationFactorUL) or a
DCI indicating that the number of slots aggregated for the PUSCH
transmission is 2.
[0128] In Method 120, a part of the time domain resource allocation
information may be configured (e.g., indicated) to the terminal for
each PUSCH instance. For example, the base station may inform the
terminal of a start symbol and a length L of each of the PUSCH
instances. This may be referred to as `Method 121`. As an index of
the start symbol of the PUSCH instance, a symbol index S in a slot
may be used. The symbol index S may indicate a relative distance
from a previous slot boundary to the start time of the PUSCH
instance. This may be referred to as `Method 122`.
[0129] The exemplary embodiments shown in FIGS. 4A and 4B may be
performed by Method 121 or Method 122. When Method 122 is applied
to the exemplary embodiment shown in FIG. 4A, the base station may
inform the terminal of (S, L)=(10, 4) configured for the first
PUSCH instance, and may inform the terminal of (S, L)=(0, 4)
configured for the second PUSCH instance. When Method 122 is
applied to the exemplary embodiment shown in FIG. 4B, the base
station may inform the terminal of (S, L)=(10, 4) configured for
the first PUSCH instance, and may inform the terminal of (S, L)=(3,
3) configured for the second PUSCH instance.
[0130] Method 120 and the detailed methods of Method 120 may be
used for slot-based PUSCH repetitive transmission. For example, in
Method 120 to Method 122, a plurality of PUSCH instances may be
mapped to different slots. In this case, the number of slots
aggregated for PUSCH transmission may be equal to the number of
PUSCH instances. Accordingly, the terminal may receive information
indicating the number of slots or the number of PUSCH instances
aggregated for PUSCH transmission from the base station. The
information indicating the number of slots aggregated for PUSCH
transmission may be transmitted using the above-described signaling
scheme.
[0131] FIG. 6 is a timing diagram illustrating a sixth exemplary
embodiment of a method for repetitive transmission of a PUSCH in a
communication system. For example, FIG. 6 may illustrate Method 120
and the detailed methods of Method 120.
[0132] Referring to FIG. 6, the base station may schedule PUSCH
repetitive transmission for uplink URLLC transmission of the first
terminal. In this case, it may be assumed that five symbols are
needed to ensure transmission reliability of the PUSCH, and the
first terminal may transmit the PUSCH after at least four symbols
from a reception completion time of an uplink grant. In this case,
the base station may determine that the twelfth to fourteenth
symbols of the slot n are used for the first PUSCH instance for the
first terminal. In addition, it may be assumed that a PDSCH (e.g.,
PDSCH by semi-static or semi-persistent scheduling) for the second
terminal is transmitted in the third to fourth symbols of the slot
n+1 and a PUCCH for the third terminal is transmitted in the sixth
symbol of the slot n+1.
[0133] In this case, the earliest time when the second PUSCH
instance for the first terminal can be transmitted without causing
interference to the second terminal and the third terminal in the
slot n+1 may be the seventh symbol. Accordingly, the base station
may determine that the seventh to eighth symbols of the slot n+1
are used for the second PUSCH instance for the first terminal. In
this case, according to Method 120, the base station may signal
resource allocation information for the first and second PUSCH
instances to the first terminal. According to Method 121, the
resource allocation information may include information indicating
a start symbol and a length of each of the PUSCH instances.
[0134] According to Method 122, the base station may inform the
terminal of (S, L)=(11, 3) configured for the first PUSCH instance,
and may inform the terminal of (S, L)=(6, 2) configured for the
second PUSCH instance. In addition, the base station may inform the
first terminal of a slot offset (e.g., 0) and/or a PUSCH mapping
type (e.g., type B) for each of the PUSCH instances.
[0135] The start symbol and the length for the PUSCH instance in
Method 121 may be defined differently from the start symbol and the
length for the PUSCH instance in Method 122. For example, the start
symbol of the first PUSCH instance may be a relative distance
(e.g., symbol offset) with one symbol (e.g., a start symbol or end
symbol) among symbol(s) occupied by a PDCCH including the uplink
grant. In the exemplary embodiment shown in FIG. 6, the symbol
offset may be 5.
[0136] In another example, the start symbol of the PUSCH
instance(s) after the first PUSCH instance may be indicated as a
relative distance with one symbol (e.g., a start symbol or end
symbol) among symbol(s) constituting the previous PUSCH instance.
In the exemplary embodiment shown in FIG. 6, the start symbol of
the second PUSCH instance may be indicated by a symbol offset
(e.g., 7) between the end symbol of the first PUSCH instance and
the start symbol of the second PUSCH instance.
[0137] Meanwhile, a PUSCH instance preceding a certain PUSCH
instance (e.g., a PUSCH instance immediately before the certain
PUSCH instance) may be a PUSCH instance for the same TB or may be a
PUSCH instance for another TB. For example, in the latter case, one
uplink grant or one configured grant resource configuration may
schedule a plurality of PUSCH instances for a plurality of TBs, and
each TB may be transmitted through one or more PUSCH instances. In
this case, the uplink grant or the configured grant resource
configuration may include time domain resource allocation
information (e.g., information about a start symbol, a length, a
start slot, etc.) for the plurality of PUSCH instances. A certain
TB among the plurality of TBs may be repeatedly transmitted through
the plurality of PUSCH instances according to the methods according
to the present disclosure. In this case, if PUSCH instance(s)
preceding the plurality of PUSCH instances for the certain TB are
allocated together, the start symbol of the first PUSCH instance of
the certain TB may be indicated by a relative distance with one
symbol among symbol(s) constituting a PUSCH instance for another
previous TB (e.g., a TB immediately before the certain TB).
[0138] Meanwhile, in the following exemplary embodiments, some of
the PUSCH instance(s) constituting the PUSCH repetitive
transmission may be dropped. In this case, the start symbol of the
PUSCH instance(s) after the first PUSCH instance may be indicated
as a relative instance with one symbol (e.g., a start symbol or end
symbol) among symbol(s) constituting the previous PUSCH instance
that has not been dropped (e.g., the PUSCH instance that has been
actually transmitted by the terminal).
[0139] The terminal may determine which slot each PUSCH instance is
allocated to by determining the position of the start symbol of
each PUSCH instance through the above-described methods. Therefore,
in the proposed methods, the base station may not separately inform
the terminal about which slot each PUSCH instance is mapped to.
When it is determined that a PUSCH instance is allocated to a
plurality of slots through the above-described methods, the
terminal may regard resource allocation of the corresponding PUSCH
instance as an error and may not transmit the corresponding PUSCH
instance. Also, the terminal may not transmit PUSCH instance(s)
after the corresponding PUSCH instance. It may not be expected in
the terminal that such the case (e.g., the error in resource
allocation of the PUSCH instance) occurs.
[0140] For another example, the start symbol of each PUSCH instance
may be indicated by a relative distance from a reference time point
(e.g., the first symbol of flexible symbol(s) and uplink symbol(s))
according to the slot format of the corresponding slot. In this
case, the base station may signal to the terminal information on
which slot each of PUSCH instance (e.g., PUSCH instances except the
first PUSCH instance) is mapped to. The methods described above may
be used in combination with Method 122. The above-described methods
may be applied to some PUSCH instances, and Method 122 may be
applied to the remaining PUSCH instances. For example, one of the
methods described above may be applied to the first PUSCH instance,
and Method 122 may be applied to subsequent PUSCH instance(s).
[0141] The above-described methods may be applied to communications
according to the dynamic grant-based scheduling. For example, when
a PUSCH is scheduled by a DCI with a CRC scrambled by C-RNTI or
MCS-C-RNTI, the above-described methods may be applied. In
addition, the above-described methods may be applied to
communications according to the configured grant or semi-persistent
scheduling (e.g., transmission of PUSCH and PDSCH).
[0142] Methods for determining the position of the start symbol of
each PUSCH instance in communications according to the configured
grant and semi-persistent scheduling may be identical or different.
In addition, the methods described above may also be applied to a
case in which a configured grant based PUSCH or a semi-persistently
scheduled PDSCH is dynamically scheduled by a DCI (e.g., a DCI for
activating or reactivating configured grant resources) with a CRC
scrambled by CS-RNTI. In this case, even when communications
according to the configured grant are performed, the scheduling
scheme may be the same as the scheduling scheme according to the
dynamic grant.
[0143] Meanwhile, in Method 120 to Method 122, a plurality of PUSCH
instances may be mapped to one slot. In this case, the PUSCH may be
repeatedly transmitted on a minislot basis or a subslot basis. This
may be referred to as `Method 123`. Here, the number of PUSCH
instances may be different from the number of slots aggregated for
PUSCH transmission. Accordingly, the base station may transmit to
the terminal each of information indicating the number of PUSCH
instances and information indicating the number of slots aggregated
for PUSCH transmission. For example, an RRC parameter (e.g.,
aggregationFactorUL) or a DCI indicating the number of slots
aggregated for PUSCH transmission may be transmitted to the
terminal. In addition, the information indicating the number of
PUSCH instances may be signaled to the terminal in an explicit or
implicit manner. For example, when the number of PUSCH instances is
signaled in an implicit manner, the terminal may consider that the
number of PUSCH instances is equal to the number of (S, L) or
SLIVs.
[0144] Method 123 may be applied when the number of slots
aggregated for PUSCH transmission is one. For example, the terminal
may identify that the number of slots aggregated for PUSCH
transmission (e.g., aggregationFactorUL) is 1 through signaling of
the base station and that the number of PUSCH instances is 2 or
more. In this case, the terminal may assume that all PUSCH
instances are scheduled in one slot (e.g., a PUSCH start slot
indicated by a slot offset).
[0145] On the other hand, when it is identified that the number of
slots aggregated for PUSCH transmission (e.g., aggregationFactorUL)
is equal to the number of PUSCH instances, the terminal may assume
that each PUSCH instance is scheduled in each slot. Method 123 may
also be applied when a plurality of slots are aggregated for PUSCH
transmission. In this case, mapping information between the PUSCH
instance(s) and the slot(s) may be further signaled to the
terminal. In more detail, the base station may transmit to the
terminal information on which slot each PUSCH instance is mapped
to. The number of PUSCH instances per slot may be the same in all
aggregated slots. Alternatively, the number of PUSCH instances per
slot may be different for each slot.
[0146] FIG. 7 is a timing diagram illustrating a seventh exemplary
embodiment of a method for repetitive transmission of a PUSCH in a
communication system. For example, FIG. 7 illustrates an exemplary
embodiment of PUSCH repetitive transmission in one slot according
to Method 123.
[0147] Referring to FIG. 7, the base station may schedule PUSCH
repetitive transmission for uplink URLLC transmission of the first
terminal. In this case, it may be assumed that four symbols are
needed to ensure transmission reliability of the PUSCH, and the
first terminal may transmit the PUSCH after at least four symbols
from a reception completion time of an uplink grant. In this case,
a PUSCH resource for minimizing the transmission latency of the
PUSCH and ensuring that the second terminal receives a PDCCH in the
eighth symbol of the slot n may be allocated as shown in FIG. 7.
For example, the base station may determine that the sixth to
seventh symbols of the slot n are used for the first PUSCH instance
for the first terminal, and the tenth to eleventh symbols of the
slot n are used for the second PUSCH for the first terminal.
[0148] When a timing alignment value of the uplink timing of the
first terminal is shorter than one symbol length, the ninth symbol
of the slot n may serve as a guard interval. In this case, the time
domain resource allocation information of each PUSCH instance may
be signaled to the terminal by the above-described methods (e.g.,
Method 121, Method 122, etc.). For example, in Method 122, the base
station may inform the first terminal of (S, L)=(5, 2) configured
for the first PUSCH instance, and may inform the first terminal of
(S, L)=(9, 2) configured for the second PUSCH instance. In
addition, the base station may inform the first terminal of a slot
offset (e.g., 0) and/or a PUSCH mapping type (e.g., type B) for
each of the PUSCH instances. Here, the slot offset may be a slot
offset between the PDCCH including the uplink grant and the first
PUSCH instance.
[0149] Information on the start symbol and the length of the PUSCH
instance may be transmitted to the terminal using at least one of
DCI, RRC signaling, and a MAC CE. In Method 122, (S, L) or SLIV of
each PUSCH instance may be informed to the terminal. For this, a
time domain resource assignment field of a DCI (e.g., uplink grant)
may be defined for each PUSCH instance or for each slot aggregated
for PUSCH transmission.
[0150] Alternatively, time domain resource allocation candidate(s)
configured by RRC signaling may include information on a plurality
of PUSCH instances or a plurality of slots aggregated for PUSCH
transmission. For example, a specific time domain resource
allocation candidate may include (S, L) or SLIV(s) for two PUSCH
instances. In this case, slot offset and PUSCH mapping type
information may be common to the plurality of PUSCH instances or
the plurality of slots aggregated for PUSCH transmission. The time
domain resource allocation candidate(s) may be preconfigured to the
terminal by RRC signaling, and one of the time domain resource
allocation candidate(s) may be indicated by the time domain
resource assignment field of the DCI (e.g., uplink grant). The
terminal may use the time domain resource allocation candidate
indicated by the time domain resource assignment field of the DCI
among the time domain resource allocation candidate(s) configured
by RRC signaling.
[0151] For example, the first time domain resource allocation
candidate configured by RRC signaling may include a first SLIV and
a second SLIV (or, first (S, L) and second (S, L)). In addition,
the first time domain resource allocation candidate may further
include a slot offset, a PUSCH mapping type, and/or an aggregation
factor. The aggregation factor may mean the number of slots
aggregated for PUSCH transmission. When a plurality of time domain
resource allocation information is signaled to the terminal, the
aggregation factor may be limited to the number of time domain
resource allocation information (e.g., SLIVs) or less. In this
case, the number of SLIVs may mean the number of PUSCH instances,
the first SLIV may correspond to the first PUSCH instance, and the
second SLIV may correspond to the second PUSCH instance.
[0152] For example, when the aggregation factor is 1, two PUSCH
instances may be scheduled in one slot. When the aggregation factor
is 2, two PUSCH instances may be scheduled in each of the two
slots. The aggregation factor may be set to be larger than the
number of time domain resource allocation information (e.g.,
SLIVs). In this case, the aggregation factor may mean the number of
PUSCH instances, and one PUSCH instance may be scheduled in each of
the slots aggregated for PUSCH transmission. For example, when the
aggregation factor is 3, the first SLIV and the second SLIV may
correspond to three PUSCH instances. One SLIV may correspond to a
plurality of PUSCH instances.
[0153] For another example, the second time domain resource
allocation candidate configured by RRC signaling may include the
first SLIV. In addition, the second time domain resource allocation
candidate may further include a slot offset, a PUSCH mapping type,
and/or an aggregation factor. When there is one SLIV, the
aggregation factor may mean the number of slots aggregated for
PUSCH transmission, and one PUSCH instance may be scheduled in each
slot. The first SLIV may correspond to all PUSCH instances. The
first and second time domain resource allocation candidates may
constitute the same RRC table. For example, the first and second
time domain resource allocation candidates may be included in PUSCH
configuration information for the same carrier and the same BWP,
and the PUSCH configuration information may be transmitted to the
terminal through RRC signaling. The base station may transmit a DCI
indicating one time domain resource allocation candidate among the
first and second time domain resource allocation candidates
configured by RRC signaling to the terminal. Here, the number of
SLIVs may be dynamically changed by scheduling of the base station.
Table 3 below may be an RRC table indicating time domain resource
allocation candidate(s) configured by RRC signaling.
TABLE-US-00003 TABLE 3 Time domain PUSCH resource allocation
mapping Slot First Second Aggregation candidate index type offset
SLIV SLIV factor 0 Type B 0 A1 -- 1 1 Type B 0 B1 B2 2 2 Type B 0
C1 C2 1
[0154] The RRC table of Table 3 may include three time domain
resource allocation candidates. The time domain resource allocation
candidate having an index of 0 may include one SLIV. This may
correspond to the existing time domain resource allocation scheme.
The time domain resource allocation candidate having the index of 0
may correspond to the above-mentioned second time domain resource
allocation candidate. The time domain resource allocation candidate
having an index of 1 may include two SLIVs, the first SLIV may be
set to B1, and the second SLIV may be set to B2. The time domain
resource allocation candidate having an index of 2 may include two
SLIVs, the first SLIV may be set to C1, and the second SLIV may be
set to C2.
[0155] According to Method 120 to Method 123, when a time domain
resource assignment field of the DCI (e.g., uplink grant) received
at the terminal indicates the index 1 or 2 of Table 3, the terminal
may consider that a PUSCH scheduled by the DCI consists of two
PUSCH instances. In this case, the terminal may determine the
symbol position of the first PUSCH instance using the first SLIV,
and may determine the symbol position of the second PUSCH instance
using the second SLIV. When the aggregation factor is 2 (e.g., when
the DCI indicates the index 2), the terminal may consider that the
first PUSCH instance is allocated to the first slot, and the second
PUSCH instance is allocated to the second slot. When the
aggregation factor is 1 (e.g., when the DCI indicates the index 1),
the terminal may consider that the first and second PUSCH instances
are allocated to the same slot.
[0156] The RRC table configuration of Table 3 is only one exemplary
embodiment of the above-described method, and the parameter set
constituting the RRC table may be configured in various forms by
the above-described method. For example, when a PUSCH mapping type
is indicated for each PUSCH instance or each TB (e.g., for each set
of PUSCH instances constituting a TB), an entry (e.g., each time
domain resource allocation candidate) of the RRC table may include
a plurality of PUSCH mapping type information. For another example,
when a slot offset is indicated for each PUSCH instance or each TB
(e.g., for each set of PUSCH instances constituting a TB), an entry
of the RRC table may include a plurality of slot offset
information. As another example, some entries in the RRC table may
not include the aggregation factor. Alternatively, a method of
interpreting the aggregation factor for each entry of the RRC table
may be different. For example, the terminal may regard the
aggregation factor as the number of PUSCH instances for some
entries, and regard the aggregation factor as the number of slots
to which the PUSCH instance(s) are mapped for some other
entries.
[0157] When the dynamic grant based scheduling scheme is used in
the above-described methods (e.g., when the PUSCH is scheduled by a
DCI with a CRC scrambled by C-RNTI or MCS-C-RNTI), time domain
resource allocation information of PUSCH instances may be signaled
to the terminal through one PDCCH (e.g., one DCI format). This
method may also be applied when the type 2 configured grant-based
scheduling scheme (e.g., when the PUSCH is scheduled by a DCI
(e.g., DCI activating or reactivating the configured grant
resources) with a CRC scrambled by CS-RNTI) is used. When a PDSCH
is repeatedly transmitted, the type 2 configured grant-based
scheduling scheme may correspond to the downlink semi-static or
semi-persistent scheduling scheme.
[0158] On the other hand, in the case of PUSCH and PDSCH
transmission according to the configured grant (or semi-persistent
scheduling), the base station may schedule a PUSCH or a PDSCH to
the terminal through RRC signaling and/or DCI. The scheduling may
continue semi-persistently until reconfigured by the base station.
In particular, a resource region (hereinafter, referred to as a
`configured grant resource`) in which the PUSCH or the PDSCH can be
transmitted may appear periodically and repeatedly, and information
indicating a periodicity of the configured grant resource and the
position of the configured grant resource (e.g., a slot or symbol
offset between the start of period and the position of the
configured grant resource) according to the periodicity may be
signaled from the base station to the terminal. The start point of
the period of the configured grant resource may be derived from a
predefined reference point. For example, scheduling information for
a type 1 configured grant PUSCH may be configured to the terminal
through RRC signaling. Scheduling information for a type 2
configured grant PUSCH and a semi-persistently scheduled PDSCH may
be configured (e.g., indicated) to the terminal through a
combination of RRC signaling and DCI.
[0159] The terminal may determine whether to transmit the PUSCH in
the configured grant resource according to the presence, shape,
size, and the like of uplink traffic. On the other hand, the
terminal may expect that the PDSCH is always transmitted in the
configured grant resource. Alternatively, the terminal may expect
that the PDSCH is opportunistically transmitted in the configured
grant resource. Initial transmission of the configured grant-based
PUSCH and PDSCH may be performed in the configured grant resource.
Retransmission of the configured grant-based PUSCH and PDSCH may be
performed on resources that are dynamically scheduled by DCI.
Re-scheduling (or, reactivation, re-initialization, or the like) of
the configured grant-based PUSCH or PDSCH and retransmission of the
configured grant-based PUSCH or PDSCH according to the
re-scheduling may be performed in a resource dynamically scheduled
by DCI. In these cases, a CRC of the DCI may be scrambled by
CS-RNTI.
[0160] In the configured grant-based transmission, the PUSCH or
PDSCH may be repeatedly transmitted. For example, the configured
grant-based PUSCH or PDSCH may be repeatedly transmitted within one
period. To this end, one or a plurality of configured grant
resource(s) may be configured to the terminal within one period.
For example, the configured grant resource(s) may be mapped within
a predetermined time period (e.g., duration), and the configured
grant resource(s) may be arranged periodically and repeatedly. One
PUSCH or PDSCH instance may be transmitted in one configured grant
resource. The plurality of PUSCH or PDSCH instances may be
transmitted in a plurality of configured grant resources (e.g.,
logically consecutive configured grant resources). In this case,
the above-described method may be used for configuring and
indicating the configured grant resource.
[0161] FIG. 8 is a timing diagram illustrating a first exemplary
embodiment of a method for configuring configured grant resources
for repetitive transmission in a communication system.
[0162] Referring to schemes a and b shown in FIG. 8, four
configured grant resources may be mapped to a predetermined time
interval (e.g., two consecutive slots). The four configured grant
resources may be repeated periodically. Referring to a scheme c
shown in FIG. 8, eight configured grant resources may be mapped to
a predetermined time interval (e.g., four consecutive slots). Eight
configured grant resources may be repeated periodically. Referring
to a scheme d shown in FIG. 8, three configured grant resources may
be mapped to a predetermined time interval (e.g., four consecutive
slots). Three configured grant resources may be repeated
periodically. Within one period, the configured grant resource(s)
may be repeatedly arranged in units of a slot or in units of a time
unit shorter than one slot.
[0163] Method 120 to Method 123 may be used for repetitive
transmission of configured grant-based PUSCH and PDSCH. For
example, in order to configure periodic configured grant resources,
A time domain resource allocation information (e.g., at least one
information of A SLIVs or A (S, L), A slot offsets, and A PUSCH
mapping types) may be configured (e.g., indicated) to the terminal.
Here, A may be a natural number. Each time domain resource
allocation information (e.g., each SLIV or each (S, L)) may be used
to determine the time domain position of at least one configured
grant resource within one period. As described above, in order to
determine the configured grant resource in the time domain, a
periodicity of the configured grant resource and an offset of the
configured grant resource (or a predetermined time interval) within
the corresponding period may be used together. The above-described
exemplary embodiments may be performed by various methods. The
exemplary embodiments below may be performed based on Method
121.
[0164] In the scheme a, two SLIVs may be signaled to the terminal
for configuration of the configured grant resources. That is, A may
be two. Within one period, the terminal may determine a start
symbol and a duration of each of the configured grant resources #0
and #1 of the first slot using the two SLIVs. In this case, the
configured grant resources #0 and #1 may be disposed in the same
slot. Two SLIVs may be equally applied in two consecutive slots.
Accordingly, the terminal may determine a start symbol and a
duration of each of the configured grant resources #2 and #3 of the
second slot using two SLIVs.
[0165] The position of symbols for the configured grant resource #0
in the slot may be the same as the position of symbols for the
configured grant resource #2 in the slot, and the position of
symbols for the configured grant resource #1 in the slot may be the
same as the position of symbols for the configured grant resource
#3 in the slot. That is, the A configured grant resource(s) may be
mapped to the same slot by the A time domain resource allocation
information, and the A configured grant resource(s) may be
repeatedly arranged in the B consecutive slots. Within one period,
AxB configured grant resource(s) may be allocated to B slots. Here,
B may be a natural number.
[0166] In the scheme b and scheme c, four SLIVs may be signaled to
the terminal for configuration of the configured grant resources.
That is, A may be four. The terminal may determine a start symbol
and a duration of each of the configured grant resources #0 to #3
in two slots of a first interval using four SLIVs. In the scheme b,
the number of periods to which the SLIVs are repeatedly applied
within one period may be 1. That is, B may be 1. In the scheme c,
the number of intervals to which the SLIVs are repeatedly applied
within one period may be 2. That is, B may be 2. Accordingly, the
terminal may determine a start symbol and a duration of each of the
configured grant resources #4 to #7 in two slots of a second
interval using four SLIVs.
[0167] The position of the slot to which each configured grant
resource is mapped may be configured to the terminal through
separate signaling. For example, the position of the slot of the
first configured grant PUSCH resource may be represented by
information about the slot offset from the start point of the
period (e.g., the first slot of the period), and the position
information (e.g., the slot offset) of the first configured grant
resource may be transmitted to the terminal. Alternatively, the
slot to which each configured grant resource is mapped or some
configured grant resources are mapped may be determined by the
SLIVs. For example, the terminal may regard S (e.g., the start
symbol of the configured grant resource) corresponding to the SLIV
as a symbol offset with one symbol (e.g., the first symbol)
constituting the previous configured grant resource. In exceptional
cases, S corresponding to the SLIV for the first configured grant
resource may mean a distance from the start point of the first slot
(e.g., offset with the first symbol of the first slot). The
terminal may obtain information indicating the offset of the
configured grant resource from the base station through signaling,
and may determine the position of the first slot to which the
configured grant resource is mapped using the offset.
[0168] In the scheme d, three SLIVs may be signaled to the terminal
for configuration of the configured grant resources. That is, A may
be three. The terminal may determine a start symbol and a duration
of each of the configured grant resources #0 to #2 in four slots
using three SLIVs. In this case, the number of intervals to which
the SLIVs are repeatedly applied may be 1. That is, B may be 1. The
specific configured grant resource may be mapped to a plurality of
slots. For example, the configured grant resource #0 may be mapped
to the first and second slots, and the configured grant resource #2
may be mapped to the third and fourth slots. This mapping operation
may be performed by configuring the SLIVs or (S, L) such that a sum
of S and L for each of the configured grant resources #0 and #2 is
greater than 14.
[0169] In the scheme d, (at most) one configured grant resource may
be limited to be started in one slot. That is, each configured
grant resource may be started in a different slot. Each of the
configured grant resources #0, #1, and #2 may be mapped to start
from the first, second, and third slots, respectively. The terminal
may assume that S corresponding to each of the first, second, and
third SLIVs is disposed in each of the first, second, and third
slots. In addition, the terminal may assume that S corresponding to
each of the first, second, and third SLIVs is a symbol derived
based on each of the first, second, and third slots.
[0170] That is, A configured grant resources may be mapped to C
consecutive slots within one period. C may be a natural number. The
position of symbols for each of the A configured grant resources
may be determined through A SLIVs. The C slots may be repeated B
times (continuously) in the time domain. In this case, A.times.B
configured grant resources may be configured by one configured
grant resource configuration, and the A.times.B configured grant
resources may be disposed in B.times.C consecutive slots.
Configuration information of the one configured grant resource may
include A SLIVs (or A time domain resource allocation information),
and may be configured (e.g., indicated) to the terminal through RRC
signaling and/or DCI. The DCI may be a DCI for scheduling a PUSCH
or PDSCH (e.g., DCI formats 0_0, 0_1, 1_0, 1_1, etc.), and one DCI
may include all SLIV(s) corresponding to the configuration
information of one configured grant resource. The base station may
signal B (e.g., repetition pattern of SLIV(s)) within one period to
the terminal explicitly or implicitly. For example, the terminal
may obtain a parameter (e.g., aggregation factor) configured by the
base station, and may interpret that the parameter (e.g.,
aggregation coefficient) is B. Alternatively, B may be explicitly
configured to the terminal by a new parameter.
[0171] The above-described exemplary embodiments may correspond to
a case in which the terminal is instructed or configured to
repeatedly transmit a PUSCH for one TB through one scheduling.
However, this is only a specific exemplary embodiment, and the
methods according to the present disclosure may be used for PUSCH
repetitive transmission of a specific TB when the terminal is
instructed or configured to transmit PUSCH for a plurality of TBs
through one scheduling.
[0172] In the above-described methods, frequency domain resource
allocation information may be commonly applied to all data channel
instances (e.g., PUSCH instances, PDSCH instances, or PSSCH
instances) for the same TB. Other scheduling information (e.g.,
MCS, HARQ process ID, new data indicator (NDI), antenna port,
number of transmission layers, power control information, etc.) may
be common to all data channel instances for the same TB. In
addition, configuration of QCL, transmission beam, precoding, and
the like may be applied in common to all data channel instances for
the same TB.
[0173] Meanwhile, as described above, a different RV may be applied
to each data channel instance for the same TB. For example, a value
of 0, 1, 2, or 3 may be used as the RV for each data channel
instance. The RV of the first data channel instance may be informed
by the base station to the terminal by DCI or RRC signaling. The
RV(s) of the data channel instance(s) after the first data channel
instance may be determined by a predefined pattern according to the
RV of the first data channel instance. Alternatively, an RV for
each data channel instance may be signaled to the terminal.
Alternatively, the terminal may determine the RV for each data
channel instance, and transmit each RV together with the
corresponding data channel instance to the base station. For
example, the uplink control information including the RV may be
mapped to a part of the resource region of the PUSCH instance, and
the corresponding uplink control information may be transmitted to
the base station together with the PUSCH instance. In this case,
separate channel coding may be applied to the uplink control
information including the RV and the UL-SCH of the PUSCH instance.
For example, a polar code may be applied to the former (i.e.,
uplink control information), and a low-density parity check (LDPC)
code may be applied to the latter (i.e., PUSCH instance).
[0174] In case of the configured grant based PUSCH (or
semi-persistently scheduled PDSCH), the pattern of RVs applied to
the respective configured grant resources may be predefined in a
standard specification. Alternatively, the base station may
configure (e.g., indicate) a pattern of the RVs applied to the
respective configured grant resources. For example, the RV pattern
may be (0, 2, 3, 1). In this case, within one period, the RV may be
sequentially applied from the first configured grant resource in
the order of 0, 2, 3, 1, 0, 2, 3, 1, . . . , and the like. As
another example, the RV pattern may be (0, 3, 0, 3) or (0, 0, 0,
0). The base station may start the PDSCH repetitive transmission in
the configured grant resource to which RV=0 is applied, and the
terminal may start the PUSCH repetitive transmission in the
configured grant resource to which RV=0 is applied. For example,
the terminal may transmit the first PUSCH instance in the
configured grant resource to which RV=0 is applied, and may
sequentially transmit the PUSCH instance(s) after the first PUSCH
instance in the subsequent configured grant resource(s). When there
are a plurality of configured grant resources to which RV=0 is
applied within a period of one configured grant resource, the
terminal may perform PUSCH repetitive transmission from one
configured grant resource among the plurality of configured grant
resources to which RV=0 is applied. Alternatively, the terminal may
start the repeated PUSCH transmissions in the first configured
grant resource to which RV=0 is applied.
[0175] In the configured grant-based repetitive transmission, the
number of PUSCH instances actually transmitted within one period
(or consecutive periods) may vary according to the start time of
the PUSCH (or PDSCH) repetitive transmission. The terminal may
repeatedly transmit the PUSCH until the last configured grant
resource within the same period regardless of the start time of the
repetitive PUSCH transmission. Alternatively, the number (e.g.,
maximum number) of PUSCH instances transmitted within one period
may be configured to the terminal. For example, in a communication
system supporting URLLC services, the maximum number of PUSCH
instances that a terminal can transmit within one period may be set
to 2 due to a limitation of latency.
[0176] The above-described methods may be applied when the PUSCH
mapping type B is used. When the PUSCH mapping type is set (e.g.,
indicated) to B, the terminal may expect that the above-described
resource allocation information is signaled from the base station.
Information indicating the PUSCH mapping type may be transmitted to
the terminal by DCI and/or RRC signaling for each PUSCH scheduling.
Referring to Table 2, since the range of valid S and L values when
the PUSCH mapping type A is used is limited, the PUSCH mapping type
A may not be suitable for URLLC transmission. On the other hand,
when the PUSCH repetitive transmission is for eMBB transmission,
the above-described methods may be preferably applied to the PUSCH
mapping types A and B.
[0177] The following exemplary embodiments may be signaling methods
for distinguishing the above-described resource allocation method
from the legacy resource allocation method. As a first exemplary
embodiment of the implicit signaling method, the above-described
resource allocation method may be applied when the PUSCH is
scheduled by a specific DCI format. For example, in the NR
communication system, a new DCI format having a smaller payload
size than the existing DCI formats 0_0 and 1_0 may be introduced.
The payload of the new DCI format may be set smaller than the
payloads of the existing DCI formats 0_0 and 1_0. The terminal may
assume that the above-described resource allocation method is
applied when the PUSCH is scheduled by a new DCI format. When
Method 122 is used, the terminal may consider that the time domain
resource assignment field of the new DCI format is configured
according to the above-described signaling method, and the terminal
may obtain (S, L) or SLIV for each PUSCH instance from the
corresponding time domain resource assignment field. Alternatively,
the new DCI format may be replaced with the existing DCI format
(e.g., DCI formats 0_1 and 1_1), and a method in which the terminal
reinterprets all or some fields of the existing DCI format may be
defined.
[0178] As a second exemplary embodiment of the implicit signaling
method, the above-described resource allocation method may be
applied when the PUSCH is scheduled by a DCI with a CRC scrambled
by a specific RNTI. The specific RNTI may be C-RNTI or MCS-C-RNTI.
Alternatively, the specific RNTI may be a new RNTI (e.g., second
C-RNTI). Alternatively, the specific RNTI may be an RNTI configured
by the base station to apply the above-described resource
allocation method among a plurality of RNTIs (e.g., existing RNTIs
and a new RNTI). For example, when Method 122 is used, the terminal
may consider that a time domain resource assignment field of the
DCI with the CRC scrambled by the specific RNTI is configured
according to the above-described signaling method, and may obtain
(S, L) or SLIV for each PUSCH instance from the corresponding time
domain resource assignment field.
[0179] Meanwhile, whether to apply the above-described resource
allocation method may be explicitly signaled to the terminal
through a specific field of the DCI. Alternatively, whether to
apply the above-described resource allocation method may be
implicitly signaled to the terminal through the existing field of
the DCI. For example, when Method 120 and the detailed methods of
Method 120 are used, the terminal may distinguish the
above-described resource allocation method from the existing
resource allocation method through resource allocation information
(e.g., the number of SLIVs) constituting the RRC table (e.g., the
RRC table shown in Table 3). Alternatively, the information
indicating whether to apply the above-described resource allocation
method may be configured to the terminal through separate higher
layer signaling (e.g., RRC signaling).
[0180] In the above resource allocation methods, each PUSCH
instance may include a DM-RS. When the PUSCH mapping type B is
applied, the DM-RS may be mapped to at least the first symbol of
each PUSCH instance. In this case, when the DM-RS cannot be mapped
from the first symbol of the PUSCH instance due to a certain
condition, the DM-RS may be mapped from one symbol among the
symbol(s) after the first symbol according to a predefined rule.
For example, when some PRBs of the first symbol of the PDSCH
instance overlap with a CORESET in downlink communication, the
DM-RS for demodulation of the PDSCH may be mapped from the second
symbol or to the second symbol. Meanwhile, the plurality of PUSCH
instances may share the DM-RS. When a plurality of PUSCH instances
are mapped to one slot, the first PUSCH instance of the
corresponding slot may include the DM-RS, and the DM-RS included in
the first PUSCH instance may be shared with the remaining PUSCH
instance(s). That is, the base station may demodulate all the PUSCH
instances in the slot using the DM-RS of the first PUSCH instance
in the same slot. In this case, the same QCL, transmission beam,
precoding, etc. may be applied to the PUSCH instances sharing the
DM-RS.
[0181] In the above-described methods, the maximum value of the
number of slots or the number of PUSCH instances aggregated for
PUSCH transmission may be configured to the terminal. This method
may be applied when a method in which the base station does not
signal the number of slots or PUSCH instances actually aggregated
for PUSCH transmission to the terminal is used (e.g., when Method
110 is used). For example, when the maximum value of the number of
slots aggregated for PUSCH transmission is M, the terminal may
transmit the PUSCH instances in consecutive M slots from the PUSCH
start slot. When some PUSCH instances are mapped to slots after the
consecutive M slots, the terminal may not transmit the
corresponding PUSCH instance. Here, M may be a natural number. When
one uplink grant or one configured grant resource configuration
includes PUSCH resource allocation information for a plurality of
TBs, the maximum value may be the maximum number of slots for each
TB or the maximum number of PUSCH instances for each TB.
Alternatively, the maximum value may be the maximum number of slots
for all TBs or the maximum number of PUSCH instances for all
TBs.
[0182] [TBS Determination Method]
[0183] In the NR communication system, a transport block size (TBS)
for a data channel (e.g., PUSCH, PDSCH, or PSSCH) may be determined
according to a function of the total number of REs or an
approximation of the total number of REs allocated to the data
channel (hereinafter referred to as `N.sub.RE`). The terminal may
calculate N.sub.RE'
(=N.sub.SC.sup.RB.times.N.sub.symb.sup.sh-N.sub.DMRS.sup.PRB-N.sub.oh.sup-
.PRB). Here, N.sub.SC.sup.RB may be the number of subcarriers per
RB, N.sub.symb.sup.sh may be the number of symbols allocated to the
data channel within a slot, N.sub.DMRS.sup.PRB may be the number of
REs for DM-RS per PRB considering the overhead of a DM-RS code
division multiplexing (CDM) group without data, and
N.sub.oh.sup.PRB may be an overhead value configured by the base
station. The terminal may derive the N.sub.RE from the calculated
N.sub.RE'. For example, the terminal may derive N.sub.RE according
to N.sub.RE=min (156, N.sub.RE').times.n.sub.PRB. Here, n.sub.PRB
may be the number of PRBs allocated to the terminal for the data
channel.
[0184] Then, the terminal may derive a median value N.sub.info of
information bits from N.sub.RE. For example, the terminal may
derive N.sub.info according to
N.sub.info=N.sub.RE.times.R.times.Q.sub.m.times.v. Here, R may be a
target code rate, Q.sub.m may be a modulation level, and v may be
the number of transmission layers. R, Q.sub.m, and v may be
dynamically scheduled to the terminal through DCI. Alternatively,
R, Q.sub.m, and v may be semi-persistently scheduled to the
terminal through RRC signaling.
[0185] Then, when N.sub.info is less than or equal to a reference
value, the terminal may convert N.sub.info to a quantized value
according to a predefined equation, and select a TBS having a value
closest to the converted value in a predefined table. On the other
hand, when N.sub.info exceeds the reference value, the terminal may
directly derive a TBS using N.sub.info and a predefined equation.
The above-described procedure may be applied when I.sub.MCS is
assigned with an entry having both R and Q.sub.m (e.g.,
0.ltoreq.I.sub.MCS.ltoreq.27 or 0.ltoreq.I.sub.MCS.ltoreq.28). When
I.sub.MCS is not assigned with an entry having both R and Q.sub.m,
the terminal may assume the same TBS as the previous transmission
of the same TB. When data is repeatedly transmitted, N.sub.RE' may
be the total number of REs allocated to each data channel instance
or an approximation of the total number of REs.
[0186] When the above-described resource allocation methods are
used, the durations of PUSCH instances may be different. In
addition, DM-RS overhead may be different for each PUSCH instance.
That is, the number of REs or N.sub.RE' of data may be different
for each PUSCH instance. In this case, if the above-described TBS
determination method is applied for each PUSCH instance, a
different TBS may be derived for each PUSCH instance. Therefore,
there is a need for a method of determining a common TBS for all
PUSCH instances constituting PUSCH repetitive transmission.
[0187] As a first exemplary embodiment of determining the common
TBS, the TBS may be determined based on the sum of the REs
allocated to all PUSCH instances or an approximation of the sum of
REs. For example, when the TBS determination method is equally
applied, the terminal may regard N.sub.symb.sup.sh as the sum of
the number of symbols occupied by all PUSCH instances. In addition,
the terminal may regard N.sub.DMRS.sup.PRM as the sum of the number
of REs of DM-RS per PRB for all PUSCH instances. Accordingly,
N.sub.RE' may be defined as in Equation 2 below.
N.sub.RE'=N.sup.RB.sub.sc.times.(N.sup.sh.sub.symb, o+ . . .
+N.sup.sh.sub.symb, v-1)-N.sup.PRB.sub.oh [Equation 2]
[0188] In Equation 2, N.sub.symb,i.sup.sh and N.sub.DMRS,i.sup.PRB
may be the number of symbols for the (i+1)-th PUSCH instance and
the number of REs of the DM-RS, respectively. V may be the number
of PUSCH instances. Here, it may be defined as `i=0, . . . , V-1'.
In Method 110, since a plurality of PUSCH instances are considered
as one PUSCH from a base station perspective, the TBS may be
determined based on the total number of REs. This method may be
applied to other resource allocation methods (e.g., Method 120 to
Method 123).
[0189] Meanwhile, TBS may be determined based on an average of the
number of REs allocated to each PUSCH instance or an approximation
corresponding to the average of the number of REs. The average of
the number of REs may mean an average for all PUSCH instances. For
example, when the TBS determination method is applied in the same
manner, the terminal may regard N.sub.symb.sup.sh as an average of
the number of symbols occupied by each PUSCH instance. In addition,
the terminal may regard N.sub.DMRS.sup.PRB as an average of the
number of REs of DM-RS per PRB for each PUSCH instance.
Accordingly, N.sub.RE' may be defined as in Equation 3 below.
N.sub.RE'=N.sup.RB.sub.sc.times.1/V.times.(N.sup.sh.sub.symb, 0+ .
. . N.sup.sh.sub.symb, V-1)-1/V.times.(N.sup.PRB.sub.DMRS, 0+ . . .
+N.sup.PRB.sub.HMRS, V-1)-N.sup.PRB.sub.oh [Equation 3]
[0190] The above-described TBS determination method may be
appropriate when Method 120 to Method 123 or a conventional
slot-based PUSCH repetitive transmission method is used for PUSCH
resource allocation. Also, the above-described TBS determination
method may be applied to other resource allocation methods (e.g.,
Method 110). Equation 4 may be used when a plurality of PUSCH
instances are transmitted in some slots. Equation 4 may be a
modified equation based on Equation 3. The average number of REs
may mean an average of slots aggregated for PUSCH transmission. In
Equation 4, W may mean the number of slots that are aggregated.
N.sub.RE'=N.sup.RB.sub.sc.times.1/W.times.(N.sup.sh.sub.symb, 0+ .
. . +N.sup.sh.sub.symb, V-1)-1/W.times.(N.sup.PRB.sub.DMRS, 0+ . .
. +N.sup.PRB.sub.DMRS, V-1)-N.sup.PRB.sub.oh [Equation 4]
[0191] [PUSCH Instance Dropping]
[0192] In the above resource allocation methods, the slots
aggregated for PUSCH transmission may be slots which are contiguous
in time. However, some slots may not be suitable for PUSCH
transmission. "When a slot satisfies a specific condition" or "When
a resource allocated for PUSCH instance transmission in a certain
slot satisfies a specific condition", the terminal may omit
transmission of PUSCH instance in the corresponding slot. For
example, when the number of symbols in which the PUSCH can be
transmitted in some of the slots aggregated for PUSCH transmission
is equal to or less than a reference value (hereinafter, referred
to as `N.sub.th`), the terminal may omit transmission of the PUSCH
instance in the corresponding slot. N.sub.th may be a natural
number. N.sub.th may be predefined in the specification.
Alternatively, the base station may configure N.sub.th, and may
inform the terminal of the configured N.sub.th. Alternatively, when
a PUSCH instance satisfies a specific condition regardless of slot
configuration, transmission of the corresponding PUSCH instance may
be dropped. This may be referred to as `Method 200`.
[0193] For example, symbols in which the PUSCH can be transmitted
in a slot may include flexible symbol(s) and uplink symbol(s), and
a transmission direction of the symbols may be determined according
to a semi-static slot format configuration or a dynamic slot format
indication. In the case of configured grant PUSCH, symbols in which
the PUSCH can be transmitted may include flexible symbol(s) and
uplink symbol(s) by semi-static configuration. Also, the symbols in
which the PUSCH can be transmitted may include uplink symbol(s) by
dynamic indication. Alternatively, the symbols in which the PUSCH
can be transmitted may be the above-described set of valid symbols.
The terminal may drop a certain PUSCH instance when the duration of
the corresponding PUSCH instance scheduled by the above-described
methods is not included in the above-described set of valid
symbols.
[0194] FIG. 9a is a timing diagram illustrating an eighth exemplary
embodiment of a method for repetitive transmission of a PUSCH in a
communication system, and FIG. 9b is a timing diagram illustrating
a ninth exemplary embodiment of a method for repetitive
transmission of a PUSCH in a communication system. For example,
FIG. 9A may be an exemplary embodiment of PUSCH repetitive
transmission in one slot according to Method 200 and FIG. 9A may be
an exemplary embodiment of PUSCH repetitive transmission in one
slot according to Method 210.
[0195] Referring to FIG. 9A, a PUSCH may be repeatedly transmitted
from the slot n. In the slot n+1, the sum of the number of flexible
symbol(s) and the number of uplink symbol(s) may be 1. When Nth is
1, the terminal may not transmit a PUSCH instance in the slot n+1
according to the Method 130. The above-described resource
allocation methods (e.g., Method 110 and Method 120) may be used in
combination with Method 200. For example, when the PUSCH is
scheduled to the terminal by Method 110 (e.g., when the duration of
some PUSCH instances is determined implicitly), the terminal may
determine whether to transmit the PUSCH in the slot(s) after the
PUSCH start slot through Method 200.
[0196] For another example, when the PUSCH is scheduled to the
terminal by Method 120 or the detailed methods of Method 120, the
terminal may determine the positions of the slot(s) aggregated for
PUSCH transmission in consideration of Method 200. That is, when
some slots satisfy a certain condition and are not used for PUSCH
transmission, the slots aggregated for PUSCH transmission may not
be contiguous in time.
[0197] The slots aggregated in the exemplary embodiment shown in
FIG. 9A may include the slot n and the slot n+2. In this case, the
base station may signal to the terminal each of information
indicating the aggregation factor indicating the number of
aggregated slots including the dropped slots and information
indicating the number of transmitted PUSCH instances including the
dropped PUSCH instances. That is, each of the nominal aggregation
factor and the number of transmitted PUSCH instances may be three.
The transmitted PUSCH instance may mean a PUSCH instance
transmitted from the base station to the terminal. Alternatively,
the base station may signal to the terminal each of information
indicating the aggregation factor indicating the number of
aggregated slots excluding the dropped slots and information
indicating the number of transmitted PUSCH instances excluding the
dropped PUSCH instances. That is, each of the nominal aggregation
factor and the number of transmitted PUSCH instances may be 2, and
this may coincide with the number of PUSCH instances that the
terminal actually transmits.
[0198] In the case of a configured grant-based PUSCH, the terminal
may count the number of aggregated slots including slots dropped
within one period, and count the number of transmitted PUSCH
instances including PUSCH instances dropped within one period.
Alternatively, the terminal may count the number of aggregated
slots excluding the slots dropped within one period, and count the
number of transmitted PUSCH instances excluding the PUSCH instance
dropped within one period.
[0199] Meanwhile, when a PUSCH is repeatedly transmitted, a partial
resource region of a specific PUSCH instance may not be used for
transmission. For example, a partial resource region (e.g., some
symbols) of a specific PUSCH instance may be configured as a rate
matching resource region, and the terminal may not map the PUSCH to
the partial resource region. Alternatively, UCI may be piggybacked
on the specific PUSCH instance. In this case, the size of a
resource to which UL-SCH data is mapped in the specific PUSCH
instance may be reduced. In the above-described cases, transmission
of the PUSCH instance may not help to guarantee the PUSCH
transmission reliability.
[0200] Accordingly, as another method of dropping some slots or
some PUSCH instances, when a size of a resource to which UL-SCH
data and/or UCI is mapped for a specific PUSCH instance is equal to
or less than a reference value (hereinafter, referred to as
`N.sub.sch`), the terminal may omit transmission of the
corresponding PUSCH instance. This may be referred to as `Method
210`. The size of the resource may be the number of REs to which
UL-SCH data and/or UCI is mapped. N.sub.sch may be predefined in
the specification. Alternatively, the base station may configure
N.sub.sch, and may inform the terminal of the configured N.sub.sch.
For example, N.sub.sch may be set (e.g., defined) to 0.
[0201] Method 211, which is similar to Method 210, may be defined.
In Method 211, when an effective code rate of UL-SCH data and/or
UCI is higher than a reference value for a certain PUSCH instance,
the terminal may drop transmission of the corresponding PUSCH
instance. The effective code rate may be determined by the total
number of REs to which UL-SCH data and/or UCI is mapped. In Method
211, the reference value may be predefined in the specification.
Alternatively, the base station may set the reference value used in
Method 211, and may inform the terminal of the set reference
value.
[0202] The above-described resource allocation methods (e.g.,
Method 110 and Method 120) may be used in combination with Method
210 or Method 211. In the exemplary embodiment shown in FIG. 9B,
the PUSCH may be repeatedly transmitted in the slot n and the slot
n+2. For example, when the PUSCH is scheduled to the terminal by
Method 110, a resource region (e.g., symbol position and/or
duration) of the PUSCH instance in the slot n+1 may be implicitly
determined. In this case, the terminal may determine whether to
transmit the corresponding PUSCH instance by using Method 210 or
Method 211. In the exemplary embodiment shown in FIG. 9B, the
transmission of the PUSCH instance in the slot n+1 may be
dropped.
[0203] For another example, when the PUSCH is scheduled to the
terminal by Method 120 to Method 123, the base station may signal
an SLIV for the PUSCH instance of the slot n and an SLIV for the
PUSCH instance of the slot n+2 to the terminal. In this case, there
is a need for a method for the terminal to identify that a PUSCH
instance is not allocated in the slot n+1. To this end, the base
station may signal information on a slot or PUSCH instance
corresponding to each SLIV to the terminal. Alternatively, the base
station may transmit the SLIV for the dropped slot or the dropped
PUSCH instance, and the corresponding SLIV may be set to NULL or a
value corresponding to NULL.
[0204] When the SLIV received from the base station is NULL or a
value corresponding to NULL, the terminal may omit the transmission
of the slot or PUSCH instance corresponding to the SLIV. In the
exemplary embodiment shown in FIG. 9B, the base station may
transmit three SLIVs to the terminal for the slot n to the slot
n+2. Here, the SLIV for the slot n+1 may be set to NULL. The
above-described methods may be applied even when a PUSCH is not
repeatedly transmitted (e.g., when a single PUSCH is transmitted in
a single slot).
[0205] Even when transmissions of some PUSCH instances are dropped,
the RVs applied to the respective PUSCH instances constituting
repetitive transmission may not be changed. For example, it may be
assumed that the RV pattern is (0, 2, 3, 1), and three PUSCH
instances are scheduled for PUSCH repetitive transmission. In this
case, "when the PUSCH is a configured grant-based PUSCH" or "when a
DCI indicating that the RV applied to the PUSCH is 0" is received,
the RVs applied to the first, second, and third PUSCH instances may
be 0, 2, and 3, respectively. Even when transmission of the second
PUSCH instance is dropped, the RVs applied to the first and third
PUSCH instances may be 0 and 3, respectively, without change.
[0206] Alternatively, when the transmissions of some PUSCH
instances are dropped, the RV(s) of the PUSCH instance (s) after
the dropped PUSCH instance may be changed. When the RVs applied to
the first, second, and third PUSCH instances are 0, 2, and 3,
respectively, and the transmission of the second PUSCH instance is
dropped, the RV applied to the third PUSCH instance may be changed
from 3 to 2. That is, the RV pattern may be applied to PUSCH
instances that are actually transmitted without being dropped.
[0207] The above-described method may also be applied to downlink
communication. When the PDSCH is scheduled to be repeatedly
transmitted, the terminal may omit a reception operation for a
specific slot or PDSCH instance when a certain criterion is
satisfied. The terminal may assume that the PDSCH instance omitted
in the reception procedure is not transmitted from the base
station. In this case, the terminal may receive another signal
and/or channel in the resource region of the PDSCH instance omitted
in the reception procedure. The criterion for omitting transmission
and reception of the specific PDSCH instance may be the same as or
similar to the criterion for omitting transmission and reception of
the above-described PUSCH instance. The above-described method may
be applied even when the PDSCH is not repeatedly transmitted (e.g.,
when a single PDSCH is transmitted in a single slot).
[0208] [Method for Transmitting PUSCH in Downlink Symbols]
[0209] In general, the terminal cannot transmit a PUSCH in a symbol
designated as a downlink symbol by slot format configuration. The
slot format configuration may include semi-static slot format
configuration and dynamic slot format configuration by SFI.
However, in order to satisfy transmission reliability and latency
requirements in the communication system supporting URLLC services,
the terminal may transmit a PUSCH in downlink symbols. For example,
when a PUSCH resource region scheduled by the base station includes
downlink symbols, the terminal may transmit the PUSCH in the
corresponding downlink symbols. In addition, when a PDSCH resource
region scheduled by the base station includes uplink symbols, the
terminal may receive the PDSCH in the corresponding uplink symbols.
This may be referred to as `Method 300`.
[0210] The downlink symbols used for the PUSCH transmission may be
downlink symbols indicated by slot format configuration information
received at the terminal before the reception of the DCI (e.g.,
uplink grant) including the scheduling information of the PUSCH.
The downlink symbols used for the PUSCH transmission may be symbols
overridden to be downlink symbols by an SFI after being configured
as flexible symbols by a semi-static slot format configuration.
That is, even when a specific symbol is configured as a downlink
symbol, the base station may improve the URLLC transmission
performance by scheduling the downlink symbol to be used for uplink
URLLC transmission.
[0211] Information indicating whether Method 300 is applied may be
signaled from the base station to the terminal. For example,
information indicating whether Method 300 is applied may be
included in a DCI. In this case, the information indicating whether
to apply Method 300 may be included in an existing field of the DCI
or may be represented by a separate indicator (e.g., an indicator
of 1 bit). In uplink communication, the DCI may be an uplink grant
scheduling a PUSCH, and in downlink communication, the DCI may be a
DCI scheduling a PDSCH. The DCI including information indicating
whether Method 300 is applied may follow a specific DCI format.
[0212] For example, in the NR communication system, a DCI including
information indicating whether Method 300 is applied may follow a
new DCI format having a payload size smaller than those of the
existing DCI formats 0_0 and 1_0. For another example, the DCI
including information indicating whether to apply Method 300 may be
a DCI with a CRC scrambled by a specific RNTI. The specific RNTI
may be an RNTI determined by the methods described above. A PUSCH
scheduled by a `DCI conforming to the new DCI format` or a `DCI
with a CRC scrambled by a specific RNTI` may be transmitted in
downlink symbols. That is, the terminal may expect that a resource
region allocated for the PUSCH includes downlink symbols, and may
transmit the PUSCH in a resource region scheduled by the base
station regardless of whether the resource region allocated for the
PUSCH includes downlink symbols.
[0213] As a different method from Method 300, the base station may
override a symbol previously configured as a downlink symbol to a
flexible symbol or an uplink symbol through an SFI. When the
transmission direction of the same symbol is indicated differently
by a plurality of SFIs, the terminal may apply the most recent SFI
to the corresponding symbol. When the SFI is received before or at
the same time as the reception time of the uplink grant for the
URLLC PUSCH, the terminal may transmit the PUSCH in the symbols
overridden as flexible or uplink symbols by the corresponding
SFI.
[0214] [Frequency Hopping Method and Multi-Beam Transmission
Method]
[0215] Frequency hopping and multi-beam transmission may be applied
to PUSCH repetitive transmission to obtain frequency and spatial
diversity. In the NR communication system, frequency hopping for
PUSCH may be used with a resource allocation type 1. The resource
allocation type 1 may be a method of scheduling a frequency
resource region to which a PUSCH is allocated based on a start
virtual resource block (VRB) and the number of consecutive VRBs.
"When a frequency hopping field included in the DCI indicates that
frequency hopping is applied` or `when frequency hopping is
configured to be applied by RRC signaling for configured
grant-based transmission`, the terminal may transmit the PUSCH
according to frequency hopping.
[0216] In the above-described method, frequency hopping may be
applied between a plurality of PUSCH instances. For example, when
the number of frequency regions (hereinafter, referred to as
`hops`) used for the frequency hopping is defined as N.sub.f, the
terminal may transmit a k-th PUSCH instance on a mod (k,
N.sub.f)-th hop. Each of N.sub.f and k may be a natural number.
When N.sub.f is 2, the terminal may transmit an odd PUSCH instance
in the first hop and may transmit an even PUSCH instance in the
second hop. Even when some PUSCH instances are dropped by the
above-described method, the hops in which the remaining PUSCH
instances are transmitted may be maintained without change. The
offset between the frequency regions occupied by the respective
hops may be represented by the number of RBs, and the offset may be
signaled from the base station to the terminal.
[0217] In the above-described method, frequency hopping may be
applied within one PUSCH instance. For example, when the number of
symbols to which the k-th PUSCH instance is allocated is
N.sub.symb,k and N.sub.f is 2, the first floor (N.sub.symb,k/2)
symbols of the PUSCH instance may be transmitted in the first hop,
and the remaining (N.sub.symb,k-floor (N.sub.symb,k/2)) symbols of
the PUSCH instance may be transmitted in the second hop. Here,
N.sub.symb,k may be a natural number. According to the
above-described method, since N.sub.symb,k may be different for
each PUSCH instance, the number of symbols allocated to each
frequency hop may also be different for each PUSCH instance.
[0218] The frequency hopping within a PUSCH instance may be applied
to all PUSCH instances. Alternatively, frequency hopping within a
PUSCH instance may be selectively applied to some PUSCH instances.
For example, the frequency hopping may be applied to PUSCH
instance(s) having a number of symbols (N.sub.symb,k) equal to or
greater than a reference value, and the terminal may transmit the
PUSCH instance(s) having a number of symbols (N.sub.symb,k) less
than the reference value in a single frequency hop. The single
frequency hop may be the first hop. For example, the reference
value for N.sub.symb,k may be 2. Meanwhile, the PUSCH data may not
be mapped to symbols to which a DM-RS for decoding the PUSCH is
mapped. In this case, the reference value for N.sub.symb,k may be
four.
[0219] The frequency hopping may be performed in one BWP. For
example, the frequency hopping may be performed in the active
uplink BWP. The frequency hopping may also be applied to a
plurality of active BWPs (e.g., a plurality of active uplink BWPs).
The plurality of active BWPs may be BWPs configured within one
carrier. Alternatively, the plurality of active BWPs may be BWPs
configured in different carriers. In this case, the base station
may inform the terminal of the ID of the BWP corresponding to each
frequency hop and the frequency position (e.g., the position of the
start RB) within the BWP. In addition, the base station may inform
the terminal of the ID of the carrier corresponding to each
frequency hop.
[0220] A plurality of transmission beams and/or precoders may be
used for PUSCH transmission. For example, different transmission
beams and/or precoders may be applied to a plurality of PUSCH
instances. For example, when the number of transmission beams
and/or precoders is N.sub.b, the terminal may transmit a k-th PUSCH
instance using a mod (k, N.sub.b)-th transmission beam and/or
precoder. Here, each of N.sub.b and k may be a natural number. Even
when some PUSCH instances are dropped by the above-described
method, the transmission beam and/or precoder applied to the
remaining PUSCH instances may be maintained without change.
[0221] A plurality of transmission beams and/or precoders may be
used for transmission of one PUSCH instance. A set of symbols to
which each transmission beam and/or precoder is applied may be
determined in the same or similar manner to the frequency hopping
method described above. For example, when the number of symbols to
which the k-th PUSCH instance is allocated is N.sub.symb,k and
N.sub.b is 2, the first transmission beam and/or precoder may be
applied to transmit the first floor (N.sub.symb,k/2) symbols of the
PUSCH instance, and the second transmission beam and/or precoder
may be applied to transmit the remaining (N.sub.symb,k-floor
(N.sub.symb,k/2)) symbols of the PUSCH instance. This method may be
applied to all PUSCH instances constituting PUSCH repetitive
transmission. Alternatively, this method may be applied to some
PUSCH instance(s) that meet a certain condition.
[0222] In uplink communication, the base station may inform the
terminal of the transmission beam and/or precoder by indicating
(e.g., configuring) an SRS resource indicator (SRI), a transmit
precoding matrix indicator (TPMI), and/or a transmission rank. The
terminal may transmit the PUSCH instance and the DM-RS for decoding
the corresponding PUSCH instance using the same antenna port(s) as
the antenna port(s) of the SRS resource indicated by the SRI.
[0223] In downlink communication, the transmission beam may
correspond to a QCL that the terminal assumes for reception of the
PDSCH. The QCL may include various types or parameters, including a
spatial QCL (e.g., QCL-TypeD, spatial Rx parameter). QCL source
information (e.g., a set of antenna port(s) for which the terminal
can assume the same QCL as the DM-RS of the data channel instance)
for reception of a data channel instance may be predefined in the
specification. Alternatively, the QCL source information for
receiving the data channel instance may be signaled from the base
station to the terminal. The QCL source information may be included
in TCI state information transmitted through signaling, and the
signaling procedure may be performed through a combination of one
or more of RRC signaling, MAC CE, and DCI.
[0224] The frequency hopping method may be used in combination with
a method of applying multiple beams and/or multiple precoders. In
addition, the frequency hopping method and the method of applying
multiple beams and/or multiple precoders may be applied to other
resource allocation methods in addition to the PUSCH and PDSCH
resource allocation methods described above. Although the
above-described exemplary embodiments have been described as being
applied to the PUSCH, the same or similar exemplary embodiments may
be applied to other data channels (e.g., PDSCH and PSSCH) as well
as the PUSCH.
[0225] The embodiments of the present disclosure may be implemented
as program instructions executable by a variety of computers and
recorded on a computer readable medium. The computer readable
medium may include a program instruction, a data file, a data
structure, or a combination thereof. The program instructions
recorded on the computer readable medium may be designed and
configured specifically for the present disclosure or can be
publicly known and available to those who are skilled in the field
of computer software.
[0226] Examples of the computer readable medium may include a
hardware device such as ROM, RAM, and flash memory, which are
specifically configured to store and execute the program
instructions. Examples of the program instructions include machine
codes made by, for example, a compiler, as well as high-level
language codes executable by a computer, using an interpreter. The
above exemplary hardware device can be configured to operate as at
least one software module in order to perform the embodiments of
the present disclosure, and vice versa.
[0227] While the embodiments of the present disclosure and their
advantages have been described in detail, it should be understood
that various changes, substitutions and alterations may be made
herein without departing from the scope of the present
disclosure.
* * * * *